4 --> 4.0
adding drakeGradientUtil.
Profiled and optimized transposeGrad.
Added matGradMultMat using unsupported KroneckerProduct as a baseline for profiling.
matGradMultMat improvements.
added normalizeVec with gradient and second derivative.
getSubMatrixGradient.
setSubMatrixGradient.
Better templating for normalizeVec.
constexpr's instead of macros. Made a GradientType struct to allow for automatic gradient type definitions.
Implemented dHomogTrans. Will move it to drakeGeometryUtil later.
dHomogTransInv.