Added note about empty ids in async relationships issue
added failing test
updated test
made the test pass
use indexOf polyfill
Fix ajaxSuccess docblock return value
Extract function to proxy `PromiseManyArray`'s method to `content`
`PromiseManyArray` proxies `Ember.Evented` methods to its `content`
Improve warns() test helper to better handle multiple calls
Merge pull request #2421 from wecc/warns-test-helper-improvement

Improve warns() test helper to better handle multiple calls
failing test for #2007
Merge pull request #2422 from emberjs/belongsToIsLoadedTest

failing test for #2007
Don't allow empty strings as id in push/update
Merge pull request #2423 from wecc/no-empty-string-id-in-push

Don't allow empty strings as id in push/update
Relationship rollback from created state
Merge pull request #2425 from emberjs/disconnect_relationships_on_created_rollback

Relationship rollback from created state
Use the model rollback and not state machine for created records rollback
Merge pull request #2426 from emberjs/disconnect_relationships_on_created_rollback

Use the model rollback and not state machine for created records rollbac...
[DOCS] InvalidError docs missing quote
Merge pull request #2427 from craigteegarden/patch-1

[DOCS] InvalidError docs missing quote