make type registration ordering in cv2.so consistent with the declaration order (fixes the class hierarchy; see ticket #1113)

continued cleaning up the docs and fixing hyperlinks (".. index:: <name>" and ".. _<name>:" are not needed anymore)

fixed bug in opencv_stitching (corrected resize images step), added matches checking (both 1->2 and 2->1 must be presented)

a lot of small corrections to bring down the number of undocumented functions, reported by the script; added em.cpp sample

a lot of small corrections to bring down the number of undocumented functions, reported by the script; added em.cpp sample