improved things so that momentumTest passes except for the comparison to .mex.
Some v / qdot fixes.
Method rename.
Some cleanup in preparation of doing gradients for forwardKinV.
added quadFormGrad + test.
Split up computeInertiasInWorld into inertiasInWorldFrame and compositeRigidBodyInertias.
inertiasInWorldFrame gradients.
* implemented mass matrix gradient and added a test that passes
* added setSubMatrixGradient method
* moved testQuatdot2angularvel
Prep for C gradients in HandC.
Added getSubMatrixGradient. Now using it in dHdq and dAdHTimesX.
Now using getSubMatrixGradient in dinvT.
Cleaned up dinvT.
Cleaned up quadFormGrad.
More gradient stuff. Gradient versions of vectorToSkewSymmetric, twistAdjoint, motionSubspaceDotV. Updated testSpatialAccelerations.
relativeTwist gradients + test.
Both H and C gradients work now.