Adds the ability to specify the view class used by the outlet Handlebars helper

Previous to this change, the view class used was always an "OutletView" (Metamorph extension of ContainerView).  This change allows the class to be set while still defaulting to the OutletView
Create Test Adapter to keep ember-testing framework agnostic
Merge pull request #2310 from robharper/feature/outlet-viewclasses

Ability to specify the view class used by the outlet Handlebars helper
Set actions as the default run loop queue
Merge pull request #2705 from teddyzeenny/default-queue

Set actions as the default run loop queue
Use helper function to remove duplication
Remove unused variable
Merge pull request #2707 from tricknotes/use-helper-function

Use helper function
Merge pull request #2626 from teddyzeenny/ember-testing-agnostic

Keep ember-testing framework agnostic
Update Backburner.js
Treat {{#each}} as {{#each this}}

Now the following is supported:

    {{#each}}Hello, {{name}}{{/each}}

This should alleviate the silliness that all of the following are
(often) the same:

    {{#each this}}...{{/each}}
    {{#each controller}}...{{/each}}
    {{#each content}}...{{/each}}
Merge pull request #2709 from machty/single-arg-each

Treat {{#each}} as {{#each this}}
Deprecate Ember.metaPath

Private and no longer used in Ember, barely used in `ember-data`.
mask deprecation warnings (when knowingly triggering them)
Merge pull request #2710 from machty/deprecate-meta-path

Deprecate Ember.metaPath
Bring back Ember.run.currentRunLoop and Ember.run.queues
Mask deprecation warning in metaPath testing
Merge pull request #2716 from teddyzeenny/meta-deprecation

Mask deprecation warning in metaPath testing
Merge pull request #2715 from teddyzeenny/current-loop

Bring back Ember.run.currentRunLoop and Ember.run.queues
fixed a typo in the api docs