[BUGFIX beta] Give precedence to routes with more static segments. Fixes #3573
Fix typo

garentee -> guarantee
[BUGFIX beta] sync router.js

- Sync router.js
- Don't fire `error` actions on transitions that have already been
  aborted/redirected
- Closes #3162
[DOC beta] Reference the guide on Feature Flags.

[ci skip]
[DOC release] Fix template lookup documentation.

The previous documentation suggested that an `Ember.View` could specify
its `templates` property to be used for template lookup instead of using
`Ember.TEMPLATES`.

This fixes the documentation to reflect what we are actually doing for
template lookup.
Fixed small typo
Removed duplicate entry