* rename plugins to background

* rename missed directories named plugins

* fix snapshot

* fix plugins references in driver

* error when pluginsFile is used

* throw error when backgroundFile is default but plugins/index.js exists

* fix wrong usage of fs.pathExists

* update desktop-gui pluginsFIle use

* fix e2e spec

* background-guide -> background-process

* fix desktop-gui spec

* rename plugins to background

Closes #2528

- Fixes #2466 
- [Docs PR](cypress-io/cypress-documentation#1117)

Should be part of 4.0.0

- Fixes #2866

* Closes #2283 

Related:

* Docs: cypress-io/cypress-documentation#967
* cypress-on: https://github.com/cypress-io/cypress-on/pull/96

* Initial upgrade changes

* Some quick fixes

* More fixes

* Clean up exp logic and fix spread array failures

* Remove caret from package.json

* Add handling for proxies in isJquery

* iterate on flaky test, increase default command timeout

* rename ‘command:end’ to ‘internal:commandEnd’

* reanme ‘command:enqueued’ to ‘internal:commandEnqueue’

* rename ‘command:retry’ to ‘internal:commandRetry’

* rename ‘command:start’ to ‘internal:commandStart’

* rename ‘test:run:start’ to ‘test:start’

* rename ‘test:run:end’ to ‘test:end’

* rename ‘viewport:changed’ to ‘viewport:change’

* update page events to take details object

* fix issues with page event changes

* fix failing tests

* fix failing integration tests

* rename background events

* actually rename the background events

* fix tests

# Conflicts:
#	packages/driver/src/cy/commands/xhr.coffee
#	packages/driver/src/dom/jquery.coffee
#	packages/driver/test/cypress/integration/commands/xhr_spec.coffee
#
packages/server/test/support/fixtures/projects/e2e/cypress/integration/x
hr_spec.coffee

- Fixes #477

…'after:run' (#2331)

* implement before:spec, after:spec, and after:run plugin events

* ensure server events only executed if registered

* don’t execute plugin event if plugins process has been killed

* call default preprocessor directly instead of registering it as plugin

makes things more consistent because now plugins are only registered by the user. this was an exception where we registered it as a plugin, but it’s unnecessary because we can just call it directly

* fix unit tests

* await server events before proceeding

* add before:run plugin event

* pass run details to before:run event

* handle and report errors thrown in server event handlers

* wrap plugin execution in promise

* rename instances of plugin

* more rename fixes

* fix tests

* fix test

* rename events to use ‘start’ instead of ‘before’ and ‘end’ instead of ‘after’

* bump zunder to 6.3.2

* await run & spec events in interactive mode

* fix server unit tests

* fix desktop-gui tests

* fix e2e specs

* fix desktop-gui specs

* fix desktop-gui specs

* add server unit tests for run/spec events in interactive mode

* add/update desktop-gui integration tests for run/spec events

* remove console.log

…run mode

Closes #2885

* reduce race condition so that async error throws before test is finished

* fix snapshot

* update snapshot

* ensure async error isn't thrown more than once

* fix async error file structure, disable supportFile

* update snapshot

* never resolve file to try to keep whitespace output consistent