Introduce Bower for managing dependencies, prep for 3.2.1

This PR introduces a major change in how we managed Bootstrap and Fontawesome previously. The gem became a bit messy when the static install option was introduced, and we've had assets all over the place in the gem. This removes an internal dependency on therubyracer and less-rails, which has been a headache in the past in supporting Windows users.

Bower is now used as the preferred method for updating FontAwesome and Bootstrap.

Includes a new helper, IconHelper, for rendering FontAwesome icons. Includes rspec test for IconHelper.

It also removes a lot of stuff from the Readme file that now exists in the Wiki, where the community can contribute more documentation.

It moves the breadcrumbs helper to app/helpers, where it belongs.

It utilizes the vendor/ folder, where external dependencies belong.

Notice this is being merged into the develop branch. I suggest and support from now on all PR's go to develop first in line with using git-flow. 

When Bootstrap ships 3.2.1, we'll tag and release this with the updated bootstrap code.