Combine Keyboard and Joystick interface into single ROV interface

[asinha94]

So there should be a generic ROV interface (virtual base calss) which will generate/publish geometry_twist messages. This will then be implemented by the derived class of keyboard or joystick etc....

The keyboard interface we have currently is a bit lacking in documentation and useability. So might as well rewrite it using the ncurses library

[asinha94]

http://stackoverflow.com/questions/421860/capture-characters-from-standard-input-without-waiting-for-enter-to-be-pressed

[asinha94]

http://stackoverflow.com/questions/1798511/how-to-avoid-press-enter-with-any-getchar