A different approach to loading html-inspector.

In preparation for JsHint integration, this avoids pulling the html-inspector library in via the asset pipeline.
Use requirejs for styleguide js dependencies.
Fix bug in calling of requirejs callbacks.
Merge pull request #295 from moneyadviceservice/html-inspector

A different approach to loading html-inspector.
Merge pull request #293 from moneyadviceservice/styleguide-jquery-requirejs

Use requirejs for styleguide jquery dependency
Merge pull request #296 from moneyadviceservice/requirejs-fix

Fix bug in calling of requirejs callbacks.
Add jshint_ruby gem.

@jongilbraith
Very basic implementation of an asset pipeline JsHint processor.

Basic implementation nailed out while pairing with @pvcarrera.
Make jshint use the jshintrc.

Can also now use less convoluted sample code.
Remove test dependency on external jshintrc.
Simple rake task to run jshint on javascript assets.
Only lint js assets in app/assets.
Get rid of hacky stubbing of initialize.