working on bringing the mdp logic back to life
just decided to unvectorize.  saving now so I don't lose anything clever
pendulum example runs nicely enough, but have to check for correctness
fixed discretization bug.  optimized a few simple things using the profiler
brought pendulum value iteration parameters over from old example.  (and added wrapping)
added function handle visualizer and cleaned up xcubed example (to live in one file)
added grid world example
adding double integrator example
adding double integrator example
minor tweaks for lecture
adds barycentric interpolation mex
replaced matlab barycentric code with a call to mex
mdp discretization is good enough for now, but could definitely be faster if we vectorize the calls to dynamics and cost
added comment
forgot to set dt for double integrator discretization.  mintime works nicely again now
don't push the newest cmake to master from this branch
Merge pull request #395 from RussTedrake/mdp

value iteration