Ignoring unneeded files for bower

Right now whenever you install the package with bower, it will fetch everything and that's not really needed. Aside from disk space being wasted (which is not much of a problem), there could be other side effects.

My use case is a project I'm working on. I added Karma to test the application and set RequireJS. I pointed Karma to fetch every JS file on the bower directory and then it failed with stuff like:

````
Backbone.localStorage in CommonJS environment
    ✖ encountered a declaration exception
      Chrome 35.0.1916 (Mac OS X 10.9.4)
    Error: Module name "../backbone.localStorage" has not been loaded yet for context: _. Use require([])
````

Or: `Chrome 35.0.1916 (Mac OS X 10.9.4) ERROR: 'There is no timestamp for /base/static/js/support/jquery.js!'`

Which I wasn't using. To fix this I had to add this to Karma:

`'static/libs/backbone.localStorage/spec/*.js'`

This changes to the bower file ensures no one will ever face this problem again.