More ES3 fixes.

Still need to conditionally switch on browsers that do not have ES5 compliant accessors, because isEnabled is compiled out based on development vs production build.
Merge pull request #5535 from krisselden/mandatory-setter-es3-fix

Fix for ES3 browsers in development mode.
[DOC] Small grammar fix on enumerable filter method
Merge pull request #5545 from shama/typo

[DOC] Small grammar fix on enumerable filter method
[DOC release] fixed spelling error in dag.js docs
Merge pull request #5551 from davidpett/patch-1

[DOC release] fixed spelling error in dag.js docs
Multiline
Merge pull request #5554 from twokul/multiline

Multiline
Update ember-cli to 0.0.44.
Merge pull request #5561 from rwjblue/update-ember-cli

Update ember-cli to 0.0.44.
Make _view a special prefix instead of a keyword
Merge pull request #5574 from mmun/view-prefix

Make _view a special prefix instead of a keyword