Package bootstrap-theme.css too.

Bootstrap-theme.css is distributed in the main bootstrap 3 zip-ball (see [what’s included](http://getbootstrap.com/getting-started/#whats-included).)
It provides drop-shadow and gradients on buttons, menus, panels &c for those who want them.

If you want to release this, I'm not sure what the version number should be.  Maybe `3.0.0.post1`?