WIP: make surface curvature work in physical space
WIP: make surface curvature work in physical space

needs more effort to get area calculations.  but these curvature calculations appear to
clarify the definition of the surface region based only on the local orthonormal frame.

DaisukeMiyamoto/ANTs,stnava/ANTs,fbudin69500/ANTs,DaisukeMiyamoto/ANTs,dawnsong/ANTs,fliem/ANTs,stnava/ANTs,DaisukeMiyamoto/ANTs,dawnsong/ANTs,fliem/ANTs,stnava/ANTs,stnava/ANTs,fbudin69500/ANTs,DaisukeMiyamoto/ANTs,dawnsong/ANTs,fbudin69500/ANTs,DaisukeMiyamoto/ANTs,fliem/ANTs,fbudin69500/ANTs,fbudin69500/ANTs,dawnsong/ANTs,dawnsong/ANTs,dawnsong/ANTs,fbudin69500/ANTs,DaisukeMiyamoto/ANTs,fliem/ANTs,dawnsong/ANTs,DaisukeMiyamoto/ANTs,stnava/ANTs,fliem/ANTs,fliem/ANTs,fbudin69500/ANTs,stnava/ANTs,stnava/ANTs,fliem/ANTs