new implementation of gpu::PyrLKOpticalFlow::dense (1.5 - 2x faster)
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modified data matrix detection interface (that does not use any new data structures). Added Python sample for data matrix detection. Ticket #1664

added dedicated <modname>_init.cpp files with initModule_<modname>() functions and all the relevant structures; made BackgroundSubtractorMOG/MOG2 derivatives from Algorithm; cleaned up MOG2 implementation and made it multi-threaded.

Setting camera parameters on Android 2.2.2 fixed. Old Android does not support continuous-video focus mode.

Performance problems fixed. Shared camera buffer is used.

Suppressed hundreds of useless MSVC warnings (can be reenabled setting cmake variable ENABLE_NOISY_WARNINGS to ON). Fixed some of remaining warnings.