adds robotiq urdf from alexg
robotiq hand model was bringing drake to it's knees.  turns out the rbm object was 3.5 GB in memory.  after a painfully slow debugging process, we figured out that it was because the loop joints, and drakeFunction kinematic constraints, contained a copy of the manipulator, which nested into a massive memory alloc.  the stopgap solution is to zap the system constraints for the copy of the rbm that is stored inside the kinematic constraint class.
adds robotiq urdf from alexg
robotiq hand model was bringing drake to it's knees.  turns out the rbm object was 3.5 GB in memory.  after a painfully slow debugging process, we figured out that it was because the loop joints, and drakeFunction kinematic constraints, contained a copy of the manipulator, which nested into a massive memory alloc.  the stopgap solution is to zap the system constraints for the copy of the rbm that is stored inside the kinematic constraint class.
dt simulate didn't work for systems with no outputs
position constraints give higher derivatives now, so geval is not needed here
Merge branch 'handsim' of https://github.com/RussTedrake/drake into handsim
fixed bug in lcp missed constraint logic.  yikes.
lcp cache is a shared data handle (so it can be used between calls)
minor cleanup
Merge branch 'handsim' of https://github.com/RussTedrake/drake into handsim

Conflicts:
	systems/plants/TimeSteppingRigidBodyManipulator.m
resolves #512
handle empty active set
remove state constraints for tsrbm
Merge pull request #515 from RussTedrake/handsim

Adds robotiq hand model and a few important bug fixes