Make detection of x64 using the gcc's target triplet identical
to the one used in cmake/OpenCVDetectCXXCompiler.cmake.
Otherwise, MinGW-w64 setups will always be treated as x64 since
they contain "w64" as vendor key.

Fix typo that would always lead to detection of x86 for MinGW
builds in the OpenCVConfig.cmake file.

MinGW-w64 always uses "w64" as vendor key which the previously
used check for "64" anywhere in the target triplet matched. This
would lead to MinGW-w64 setups always being treated as x64.

Turns out we do not even need this additional check since the
architecture has been correctly determined earlier in this file.
No need to do it again.

added video writer quality, which user may change dynamically in the case of motion jpeg; enabled NEON intrinsics in the encoder

disable cuda::FastOpticalFlowBM if configured without cudaarithm

Fix a typo in first equation under method=CV_TM_CCOEFF.