functionhandleconstraint --> functionhandledifferentiableconstraint
and made a real functionhandleconstraint class.
moving xdim up from DifferentiableConstraint to Constraint
basic rrt implementation
clean up plotting
removed tolerance in favor of goal bias
Revert "functionhandleconstraint --> functionhandledifferentiableconstraint"

This reverts commit 617d42e05a97264efa67c1804bcfdbad2c94e9a1.

Conflicts:
	solvers/FunctionHandleConstraint.m
cleaned up gradient handling in Constraint.eval ; subclasses can specify grad_level.  Zapped DifferentiableConstraint, which was getting in the way and is now unnecessary
propagating grad_level logic
fixing unit tests
vestigial lcmgl calls were failing on mac, but weren't even used
fix output logic
template for kinematic motion planning
adds warning to fmincon output.  sheds light on our mysterious, non-reproducible build server issue #135
hongkai's code review comments
needed to update test for linear constraint, too
Merge pull request #237 from RussTedrake/rrtx

cleans up constraint classes and implements basic rrt.