chore(build): Add release task

Here is a release task.  It uses shelljs, which is super awesome and cleaner than callback hell.

It now copies the build files from `dist` to the repository root and commits those every release.  This makes it easy for people to get whatever is latest without bower.

TODO: Add bower release to the task.  Perhaps just make the bootstrap-bower a submodule  and copy release files there then push bootstrap-bower. Or just ignore bower for now because it will change soon.

TODO: Add push-to-cdnjs task.