Bastion: Adds Grunt task to pick the proper library files for each

JavaScript library defined in bower.json in order to check the minimal
amount of third party libraries into source control.

Adds two new tasks for managing JavaScript libraries. The first,
'grunt bower:update' resolves dependencies listed in bower.json and
places the specified library files into the proper locations. This is
done because not all bower based libraries include only the needed files.
The task 'grunt bower:dev' is available for building the testing environment
and pulling down libraries needed for testing only.