Moved all messages to the messages/ folder.
This meant changing a lot of includes and things.
Small tidying up.
Took out unneeded gensrv() in buttons, which caused a compilation warning, and made miniscule style changes to motors.cpp.
Created structure for buttons node. Compiles. However event_button function is not written.
Added buttons and cliffsensor ROS nodes. Everything except for src/<node>.cpp file functions have been changed.