Simple Torque feedback for hinge joint only
Added working joint F\/T output

Joint force and torque is extracted by the standard ODE feedback
structure, then the equivalent wrench is found at the joint anchor
point. The signs of the returned force and torque are from link1's
perspective. F/T applied to link2 are equal and opposite.
Simplified ODE force and torque conversion
misc cleanup and logging
Spelling fix on Sync callback
Candidate changes for COM
Working test with a single sphere
Used simpler COMOffset instead of full mass frame
Added debug messages to track source of joint explosion
Removed joint anchor COM subtraction, seems to work now
Add surface layer setting for better collision stability
Fixed comments 1,2
Rewrote GetLinkForceTorque to use only KinBody functions
Removed unnecessary rotation in InitKinBody
Fixed overlooked issue
Merge pull request #256 from robEllenberg/feature/odefixes

initial feature/odefixes, the ode syncing might be unstable