[BUGFIX beta] Remove old reference to invoker.

As of 6a8137902da56b8b1060fcd0bdb748d5e7ae0092 we no longer use a custom
`invoker`, and the logic was moved into `registerObserver` directly.
[BUGFIX beta] Update the yuidoc paths to the new packages_es6 directory.
fix readme inconsistencies
Merge pull request #4693 from bmac/fix-doc-build

[BUGFIX beta] Update the yuidoc paths to the new packages_es6 directory.
[DOC release] fix sample code inconsistencies
[BUGFIX beta] RSVP errors go to Ember.onerror if present
Merge pull request #4597 from knownasilya/typo

[DOC release] comment examples and consistencies
Merge pull request #4696 from knownasilya/readme

Fix README inconsistent quotes
[DOC release] fix documentation for childViewDidChange for number added
Merge pull request #4686 from rjackson/fix-removed-invoker

[BUGFIX beta] Remove old reference to invoker.
[DOC release] Add yui doc @since tags to methods and properties added after 1.0.0
Merge pull request #4697 from jhsu/fix-doc-var-name-for-childviewsdidchange

[DOC] fix documentation for childViewDidChange for number added
Merge pull request #4694 from bmac/since-docs

[DOC beta] Add yui doc @since tags to methods and properties added after...