Ember.Select shouldn't trigger change for when content is an empty array-like obejct
The previous check for triggering when content was empty relied on
the falsiness of `[]` but would incorrectly trigger change when the
content was an Array-like object whose proxied `length` was 0.

Specifically this would cause issues with setting the `contentBinding`
of a Select to the `DS.Model.find` values that are empty initially
setting the Select's `selection` from whatever the current value is to
`undefined` when change was triggered on an empty content.

Asynchronously, data would return and the content would become populated
but the selection value had already been unset.
Make outlets work inside block helpers
Always bind outlet to the template from whence it came
Adding unit test for nested outlets
sub containers should inherit resolver
Merge pull request #1706 from tchak/sub-containers-resolver

sub containers should inherit resolver
make container a module
Complete concatenated properties doc

Documenting the feature of adding a single property should just add it into the related array
Merge pull request #1710 from sly7-7/patch-1

Complete concatenated properties doc
Merge pull request #1707 from tchak/container-as-module

make container a module
Fix trailing slash issue. Fixes #1691
Merge pull request #1708 from bobey/master

Added a VagrantFile to ease emberjs build for newcomers
Update gitignore.
Remove pointless check for native Array replace.

The real function is called splice, which is what the “shim” was calling anyway.
Move PromiseChain to old-router
Merge pull request #1715 from CrowdStrike/promise-chain-cleanup

Move PromiseChain to old-router
ArrayController learned itemControllerClass.

```javascript
App.ItemController =
  Em.ObjectController.extend();

var arrayController = Em.ArrayController.create({
  itemControllerClass: 'ItemController',
  content: Em.A([0, 1])
});

controller.objectAtContent(0);               // an instance of ItemController
controller.objectAtContent(0).get('content') // 0
```

This partially addresses #1637, but makes no attempt at supporting reusable
views.
Allow chaining on DeferredMixin#then
Merge pull request #1718 from CrowdStrike/deferred-chaining

Allow chaining on DeferredMixin#then
Merge branch 'arrayproxy-itemcontrollersclass' of https://github.com/hjdivad/ember.js into hjdivad-arrayproxy-itemcontrollersclass