Media.net adapter added

[vedantseta]

Type of change

• Bugfix
• Feature
• New bidder adapter
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Does this change affect user-facing APIs or examples documented on http://prebid.org?
• Other

Description of change

The PR adds Media.net adapter

• test parameters for validating bids.

var adUnits = [{
          code: 'div-gpt-ad-1460505748561-0',
          sizes: [[300, 250], [300,600]],
  
          bids: [{
              bidder: 'medianet',
              params: {
                  cid : '8CUX0H51C',
                  site: {
                      page: 'http://smoketesting.net/prebidtest',
                      domain: 'smoketesting.net',
                      ref: 'http://smoketesting.net/prebidtest'
                  }
              }
          }]

     }];

PR on the docs repo at prebid/prebid.github.io#549

[vedantseta]

@mkendall07 , Getting this error on Travis
Cannot start ChromeHeadless

Could you check ?
Thanks.

[vedantseta]

@mkendall07 Thanks for applying Travis patch in master. Can you please apply the same patch in legacy branch too ?

Thanks.

[mkendall07]

@vedantseta
done. thx

[matthewlane]

Tested on legacy branch, works equivalently to corresponding 1.0 adapter and receiving bids. LGTM