Implemented the lightning experienced-based planning framework

Also contains https://github.com/ompl/ompl/pull/39

See publication [A Robot Path Planning Framework that Learns from Experience](http://queue.ieor.berkeley.edu/~goldberg/pubs/berenson-ICRA2012-final.pdf)

Part of my GSoC project.
Goal is the base class (not a state necessarily). I think you want to do a dynamic cast to GoalState.