Bootstrap 3 Adapter

[ebollens]

Enough changes have happened in Bootstrap 3 that we'll need to put in some explicit work to support it and Bootstrap 2. Our SASS port of Bootstrap has been updated, so the work just rests on our plate. Ideally, Bootstrap 2 should be the default (so as not to break compatibility), but it should be easy enough to swap over to Bootstrap 3. Easiest way to do this is likely two different submodules for different versions and then push a variable into the system for 3 that tells the adapter what it should do differently. Some changes make like easier, like the removal of row-fluid and the assumption that row is always fluid, meaning that we don't have to provide a different class to let you recast row to use the non-fluid variation.