Style

Before you merge, can you (or I can with you):  
- hook up [Travis](http://travis-ci.org) with the pr2_pbd repository
- hook up [coveralls](http://coveralls.io) with the pr2_pbd repository

I would do this but I don't because I'm not a collaborator on those repos.

This pull sets up pr2_pbd to be installed on Travis (continuous integration). It also updates the README and does some small other cosmetic changes.

After many hours of attempting, I finally got everything to install on the Travis automated build system. However, the tests will not run. This is because the Gazebo version we use won't run there due to some bug. So, the tests it runs automatically are just linters.

The true tests and coverage can still be run/computed locally.