#163 Hinge and Slider Joint Damping

[John Hsu]

Apply damping based on joint velocity for slider and hinge joints.
As a first shot, ramp up % damping force based on iteration number to achieve better than explicit-damping maximum damping limit.
A better approach might be designed based on a limiter on velocity change within a single update step.

[John Hsu]

[John Hsu]

reuploaded patch, cleaned up some codes in memory allocation in quickstep.cpp and gated damping in step.cpp.

Note damping does not work with step.cpp using Dantzig's algorithm.

[Daniel K. O.]

Moved to http://bitbucket.org/odedevs/ode/issue/6/hinge-and-slider-joint-damping