Add a reference doc for the adUnit object (#558)

* Add first draft of ad unit reference

* Add examples to ad unit reference

* Add native aspect ratio info to AN adapter docs (#543)

* Add native aspect ratios to AppNexus adapter docs

Also did some general cleanup and formatting while I was in there.

* Update field defs a bit; add OpenRTB native link

* Remove OpenRTB note based on feedback

* Add banner, video, and native sections

* WIP native updates across several pages

* Tweak language in AN bidder doc links

* Edit down to a single native example; s/Ast//g

* Update native example code; s/Ast//g

* Show `mediaTypes.native.image.sizes` in examples

In addition to updating the basic examples to use sizes for images and
icons, we add a section to both the API reference and the 'Show Native
Ads' page that lists both ways to define sizes for image-like assets.

Since the content is the same, it's in a shared file sourced using the
Liquid `include` keyword.

* Fix code formatting issue with included file

* `adUnit.sizes` is ignored on native ad units

* Remove `adUnit.sizes` since banner sizes are used

* Remove redundant `adUnit.sizes` from native ad

* Use correct syntax for native "image-type" ad

* Add multiformat ad unit information (#541)

* Add multiformat ad unit information

* Update default targeting keys

* Update based on review feedback

* Change key to hb_format

* Add note about including banner media type if supported

* update tag samples with multiformat syntax (#528)

* update tag samples with multiformat syntax

* reverting part of change on show-native-ads.md

* Re-add trailing spaces to info boxes (#573)

* Add note about non-1.0 adapters (#570)

* Add note about non-1.0 adapters

* Add trailing spaces back

* suppord prebid.js 1.0 Colossusssp (#560)

* Update vertamedia.md (#567)

Update for Vertamedia Adapter description
Add examples

* Add multiformat docs: developers, ad ops, example code (#561)

* WIP multiformat docs

* Flesh out prerequisites/implementation of dev doc

* Add multi-format docs to 'Docs by Format'

* Add a quick example of *why* to do this

* Outline steps on ad ops page

* Clarify multi-format on 'Docs by format' page

* Various dev doc fixups

* Update JSFiddle, overview bullet points in example

* Update multiformat fiddle

* Key is now called `hb_format`

* s/multi-format/multiformat/

* Use 'appnexus' bidder and Prebid.js v1

* s/multi-format/multiformat/

* Be clear that it's *outstream* video

* Use title case

* Update multiformat example link

* Fill in multiformat ad ops instructions

Because these are basically the same as the banner/native instructions,
I've filled them in as the "diffs" between our existing, published,
vetted instructions.

* Add native aspect ratio info to AN adapter docs (#543)

* Add native aspect ratios to AppNexus adapter docs

Also did some general cleanup and formatting while I was in there.

* Update field defs a bit; add OpenRTB native link

* Remove OpenRTB note based on feedback

* Add banner, video, and native sections

* WIP native updates across several pages

* Tweak language in AN bidder doc links

* Edit down to a single native example; s/Ast//g

* Update native example code; s/Ast//g

* Show `mediaTypes.native.image.sizes` in examples

In addition to updating the basic examples to use sizes for images and
icons, we add a section to both the API reference and the 'Show Native
Ads' page that lists both ways to define sizes for image-like assets.

Since the content is the same, it's in a shared file sourced using the
Liquid `include` keyword.

* Fix code formatting issue with included file

* `adUnit.sizes` is ignored on native ad units

* Remove `adUnit.sizes` since banner sizes are used

* Remove redundant `adUnit.sizes` from native ad

* Use correct syntax for native "image-type" ad

* Add multiformat ad unit information (#541)

* Add multiformat ad unit information

* Update default targeting keys

* Update based on review feedback

* Change key to hb_format

* Add note about including banner media type if supported

* update tag samples with multiformat syntax (#528)

* update tag samples with multiformat syntax

* reverting part of change on show-native-ads.md

* s/multiformat/multi-format/g

* We don't need an order per demand partner

* Remove ambiguous comment on fluid vs. fixed native

* Update multi-format language in dev setup intro

* Update multi-format description based on feedback

* Update 'How it works' based on feedback

* Update ad unit language based on feedback

* Fix Prebid.org-hosted multiformat example

Somehow a native example was erroneously added -- probably as a
placeholder.  It has been replaced with a slightly modified version [*]
of the multi-format example kindly provided by @matthewlane.

[*] It was modified to (1) use Prebid.js v1.2 from the CDN and (2) to
use the 'appnexus' rather than the old AST adapter

* Update JSFiddle in multiformat example

To address the following points:

1. Removing mention of the internal dev URL as mentioned by Jacobson

2. Making the code the same as that of
   prebid.org/examples/multi_format_example.html

* Add ad unit creation step with sizing/native info

* Clarify line item setup language

* Update k-v targeting instructions per feedback

- Use slightly different language/notation

- Add screenshots

* Check in screenshots of multi-format ad ops setup

* Update native format language per feedback

* Clarify that it's banner and/or outstream

* Note bidder-specific line item targeting keys

* Update targeting description per feedback

* Update native size note, per feedback

* Fix mobile size per feedback

* Hide multi-format example from site's left nav

* Belatedly add link to the 1.0 release announcement

* Fix typo

* Use Prebid.org-hosted multi-format example

(Also, add it to the `/examples` index page.)

* s/div-banner-outstream/div-banner-native/g

* Add a third example: 'banner-outstream'

* Update examples to set `cache.url` to `false`

I'm told this is connected somehow to the following issue, but ¯\_(ツ)_/¯

prebid/Prebid.js#1976

* Update placement IDs in Prebid.org-hosted example

In order for outstream to work, we need a placement configured to work
with VAST 3.0 since that is what the test outstream creative requires.

* Update JSFiddle to use updated placement IDs

* Get banner/outstream examples working: use 300x250

Also, added a note to the JSFiddle multi-format example page that the
Fiddle works sporadically for outstream, so check out the
Prebid.org-hosted example (which works closer to 100% of the time)

* Fix broken formatting on JSFiddle example page

* update prebid version download page 1.2.0 & 0.34.2 (#580)

* update prebid version

* review update

* Provide a high-level description of an ad unit

* Remove monospacing from section headers

Also, remove some unnecessary nesting from a few headers

* Fix up anchor links to use object properties

* Add multi-format example

* Update description of `sizes` per feedback

* Update `bids` description based on feedback

* Update `mediaTypes` description

* Edit scope description for `{banner,native,video}`

* There is no `mediaTypes.native.sizes`

* Add link to docs on pre-defined native types

* Update `native.title` description per feedback

* Mark all native assets as optional

* Update `native.body` description

* `sponsoredBy` is an object

* Update `native.image` description

* Remove Prebid Native validation warning

This already exists elsewhere, on the 'Show Native Ads' page.

* Native ad validation checks for landing page URL

* `sizes` and `aspect_ratios` are both allowed

For example, see:

https://github.com/prebid/Prebid.js/blob/master/test/spec/unit/core/adapterManager_spec.js#L836

* Update `native.title.len` description

* Mark `context` as optional

* Mark `required` properties as optional

This seems to be confirmed by line 105 of `src/native.js` (as of this
writing):

```
    const requiredAssets = Object.keys(requestedAssets).filter(
        key => requestedAssets[key].required
    );
```

* Media.net bidder added (#549)

* vi bid adapter docs (#537)

* vi bid adapter docs

* VI bid adapter docs - added header

* VI adapter docs - renamed file and changed according to example

* Add : docs for NasmediaAdmixer Adapter (#536)

* Add: documentation for nasmediaAdmixer Adapter

* Add: documentation for nasmediaAdmixer Adapter

* Add: documentation for nasmediaAdmixer Adapter

* Add: documentation for nasmediaAdmixer Adapter

* Added Inskin bid adapter docs (#548)

* RockYou Adapter: Added docs for the RockYou Bidder Adapter (#551)

* Prebid v1 smart (#565)

* Fix domain sample

* Add HTTPS sample for domain parameter

* Add HTTPS sample for domain parameter

* Add Smart AdServer in the index and download list

* Add currency parameter documentation

* Revert "Merge remote-tracking branch 'refs/remotes/prebid/master'"

This reverts commit 099edc2, reversing
changes made to 07ce9fd.

* Update documentation

Specify "target" parameter development status

* Adding documentation for bidfloor parameter.

* Update our adapter documentation

* Adding Optimera doc. (#569)

* PubMatic 1.0 Adapter Updates (#530)

* PubMatic 1.0 Adapter Updates

* Remove $$PREBID_GLOBAL$$ reference

* Add prebid_1_0_supported flag

* Gjirafa bidder params documentation (#483)

* Gjirafa bidder params documentation

* Add Prebid 1.0 supported line

* Change prebid support line

* Add `body.len` to table with description

* Update `mimes`, `protocols`, `playbackmethods`

* s/sizes/playerSize/g for video ads

* Pass `placementId` as a string in examples