Robocup 0.1

This pull request merges pull request #1 with all the code we did during Patrick's visit. It allows an agent to connect with Gazebo. I've updated the instructions too.

This will require a few pull requests from gazebo.

[Pull request 1](https://bitbucket.org/osrf/gazebo/pull-request/1101)
[Pull request 2](https://bitbucket.org/osrf/gazebo/pull-request/1099)