Merge pull request #3927 from rjackson/warn_on_missing_template

[DOC beta] Assert if template for {{render}} not found.
Merge pull request #4002 from twokul/runloop-doc-fixes

[DOC beta] Several doc fixes
Merge pull request #4003 from rjackson/cleanup_tracked_array

[DOC beta] Cleanup Ember.TrackedArray docs.
Merge pull request #4001 from rjackson/view_doc_cleanup

[DOC beta] Ember.View documentation cleanup.
Merge pull request #3944 from rjackson/cleanup_unquoted_render_usage

Assert if {{render}} is called with an unquoted name.
Merge pull request #3946 from teddyzeenny/new-promise-labels

Label Promises
Merge pull request #3999 from rjackson/update_handlebars

[beta] Update handlebars to 1.2.1.
[BUGFIX release] Update Metamorph

Fixes https://github.com/tomhuda/metamorph.js/issues/30 and https://github.com/emberjs/ember.js/issues/3779
Merge pull request #4010 from ebryn/update-metamorph

[BUGFIX release] Update Metamorph
[BUGFIX release] Update Backburner.js

Includes improved debug performance
Merge pull request #4011 from ebryn/update-backburner

[BUGFIX release] Update Backburner.js
[DOC beta] Cleanup Ember.TextField docs.
Merge pull request #4012 from rjackson/cleanup_text_field_docs

[DOC beta] Cleanup Ember.TextField docs.
[DOC beta] Remove JSDoc @scope directives.

`@scope` is not a valid `YUIDoc` directive, and causes last properly
documented method/property in a file to contain the text output of any
undocumented items directly following the `@scope` directive.

Ember.Select

Before:

![screenshot](https://www.monosnap.com/image/pZCrf3m2vdqlROOUCjIuJre4a.png)

After:

![screenshot](https://www.monosnap.com/image/rfCxDtISxjm19SM85RZKbbPgK.png)

Ember.RenderBuffer

Before:
![screenshot](https://www.monosnap.com/image/ZDxRuuf9vyxMBVqIZUlghxrID.png)

After:

![screenshot](https://www.monosnap.com/image/J9eCBqdHonuB8UXC0eWQ6gQuf.png)
Merge pull request #4013 from rjackson/remove_scope_directives

[DOC beta] Remove JSDoc @scope directives.
Merge pull request #3919 from twokul/stack-trace-fixes

[beta] Replaces anonynoums functions with named ones
[BUGFIX beta] Do not use ENV if EmberENV exists.

This allows the use of `ENV` in your application without having Ember
hijack it for its uses.

To avoid using `window.ENV`, but still provide customization to Ember's
boot process you could use something like the following:

```javascript
ENV = 'DO NOT USE ME!!!!';

EmberENV = {DISABLE_RANGE_API: true};
```
[DOC beta] Cleanup ember-testing documentation.

Helper Syntax Highlighting

Before:

![screenshot](https://www.monosnap.com/image/yPzfGQTdTiZXlRpNuduM2orTs.png)

After:

![screenshot](https://www.monosnap.com/image/lUF5fcv70K8sH92X3epLjpEaM.png)

registerAsyncHelper

Before:

![screenshot](https://www.monosnap.com/image/OICLOCKAoqvapb5FIecAg2QfP.png)

After:

![screenshot](https://www.monosnap.com/image/tebGA4uwb8wMhnbEzMg8hzks5.png)

registerHelper

Before:

![screenshot](https://www.monosnap.com/image/3GXahrtQ20EYs8wKbCWJw82ws.png)

After:

![screenshot](https://www.monosnap.com/image/K4sLcekKWKURKuFaExH5DYur2.png)
Merge pull request #3991 from stefanpenner/run-loop-helpers

Ember.run.proxy + Ember.run.method
Merge pull request #4014 from rjackson/fixup_test_docs

[DOC beta] Cleanup ember-testing documentation.