some improvements on checks and static jac eval

- jacobians at identity only evaluated once, statically
- removed unnecessary and wrong internal checks

	modified:   cvt/vision/KLTPatch.h
indent and corrected distance function

	modified:   cvt/vision/slam/Keyframe.cpp
maintaining pose relative to last active keyframe

- to better cope with map changes from SBA

	modified:   cvt/vision/slam/stereo/StereoSLAM.cpp
	modified:   cvt/vision/slam/stereo/StereoSLAM.h