facerecognizer interface + white + whitespaces remove

Also, removed the one from modules/python/src2/cv.py and cleared its
executable bit, since it's not a script.

range in calcHist() changed from [0,255] to [0,256]. Otherwise, it won't count pixels with value 255. It can be verified taking sum of histogram values and checking it with image size.

added some sample description

Bug #2257: Adding a quick workaround for truncated labels on 64bit machines in the Python FaceRecognizer wrapper code. This is only a temporary bugfix, that will be fixed at a better point as soon as possible.

rewritten feature_homography.py using it
added plane_ar.py - simple augmented reality sample

building descriptor index on target capture
simple AR experiment (work in progress)

ASIFT

ASIFT

small fix in find_obj.py

- handle bad matching case
- use BFMatcher and FlannBasedMatcher (and thus fixing a bug: L2^2 metric was used for flann)