facerecognizer interface + white + whitespaces remove

ReST directive was used. Also fixed some other ReST directives that were
not correct and removed some warnings during buildbot checks.

- Used lunix style slashes - works on most systems
- Removed all trailing whitespaces

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

e.g. <opencv2/core/core.hpp> become <opencv2/core.hpp>

Also renamed <opencv2/core/opengl_interop.hpp> to <opencv2/core/opengl.hpp>

Invalid links and refences fixed.
SpaeseMat class documentation updated.

All errors were found by doc/check_docs2.py

All errors were found by doc/check_docs2.py