* Improve Documentation
Fixes Spelling Mistakes.

Add method KeypointBasedMotionEstimator::estimate(InputArray, InputArray) to support both cpu & opencl algorithm processing

the orignal estimate function has input parameters defined as "Mat", this prevent users to call into algorithm opencl path

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

if points0 is empty checkVector(2) return -1, it causes the exception

if they are not needed

OpenCV with the refactored features2d compiles! contrib is broken for now; the tests are not tried yet

OpenCV with the refactored features2d compiles! contrib is broken for now; the tests are not tried yet

An extremely rare case where, for numeric reasons bestM finds more inliers than ninliersMax. 
This RARE case causes memory corruption and a nasty seg fault.

Conflicts:
	modules/core/include/opencv2/core/cuda.hpp
	modules/cudacodec/src/thread.cpp
	modules/cudacodec/src/thread.hpp
	modules/superres/perf/perf_superres.cpp
	modules/superres/src/btv_l1_cuda.cpp
	modules/superres/src/optical_flow.cpp
	modules/videostab/src/global_motion.cpp
	modules/videostab/src/inpainting.cpp
	samples/cpp/stitching_detailed.cpp
	samples/cpp/videostab.cpp
	samples/gpu/stereo_multi.cpp