Nicer structure for String utility helpers
[beta] Publish channel builds to bower.
Merge pull request #4595 from rjackson/publish-channels-to-bower

[beta] Publish channel builds to bower.
Merge pull request #4592 from trek/split-apart-string-util-imports

Split apart string util imports
[bugfix beta] Fix #4604 ComputedPropertyPrototype.didChange only calls removeDependentKeys if the individual cache for the specific key is not undefined, instead of the cache itself
Update for publishing to bower with Travis.

Travis doesn't have an ssh-agent setup (so ssh-add -D was failing for
example).
Ensure the correct key is used for fetching components/ember.
Merge pull request #4612 from endash/fix-4604

Fix #4604 ComputedPropertyPrototype.didChange only calls removeDependent...
Add support for required property in checkbox
Merge pull request #4621 from bakura10/patch-1

Add support for required property in checkbox
[DOC] Fixed HTML closing tag in example result.
Merge pull request #4622 from jayphelps/patch-2

[DOC] Fixed HTML closing tag in example result.