remove sizecheck from main quat methods
Merge pull request #506 from RussTedrake/quat

remove sizecheck from main quat methods
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