--help message and starting run.py w/o parameters generate different messages

E. g. w/ and w/o build_path in the end

build_path is required, removing square brackets

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.