Merge remote-tracking branch 'origin/2.4'

Original pull requests:
	#996 from jet47:gpu-nvcuvid-libraries
	#995 from jet47:fix-bug-2985
	#999 from snosov1:unreliable-results-fix
	#1005 from alekcac:doc_fix
	#1004 from jet47:fix-bug-3068
	#987 from jet47:bug-3085-fix
	#969 from pengx17:2.4_binary_cache
	#929 from dominikrose:mingw-libdc1394-2-windows
	#1000 from ivan-korolev:fix_sift_bug_2892
	#1001 from ivan-korolev:fix_stitching_bug_2405
	#998 from asmorkalov:android_cmake_mips_fix
	#993 from ivan-korolev:fix_videostab_bug_3023
	#988 from snosov1:3071-fix
	#986 from pengx17:2.4_initiated_context
	#982 from pengx17:2.4_fix_two_bugs
	#981 from SeninAndrew:ximea_camera_support_fix
	#991 from asmorkalov:android_javadoc_fix
	#972 from jet47:mog2-params-bug-2168
	#980 from SpecLad:include-config
	#973 from pengx17:2.4_oclclahe
	#903 from aks2:2.4
	#968 from asmorkalov:android_na_cproj_fix
	#971 from SpecLad:matchers-ctor
	#970 from asmorkalov:dshow_valid_check_fix
	#965 from apavlenko:fix_java_empty_mats

Conflicts:
	cmake/OpenCVModule.cmake
	modules/core/src/matmul.cpp
	modules/gpu/CMakeLists.txt
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/perf/perf_imgproc.cpp
	modules/ocl/src/imgproc.cpp
	modules/ocl/src/initialization.cpp
	modules/stitching/src/matchers.cpp
	modules/video/src/video_init.cpp
	modules/videostab/src/global_motion.cpp

modules/stitching/src/matchers.cpp

@@ -64,10 +64,6 @@ struct DistIdxPair
 
 struct MatchPairsBody : ParallelLoopBody
 {
-    MatchPairsBody(const MatchPairsBody& other)
-            : matcher(other.matcher), features(other.features),
-              pairwise_matches(other.pairwise_matches), near_pairs(other.near_pairs) {}
-
     MatchPairsBody(FeaturesMatcher &_matcher, const std::vector<ImageFeatures> &_features,
                    std::vector<MatchesInfo> &_pairwise_matches, std::vector<std::pair<int,int> > &_near_pairs)
             : matcher(_matcher), features(_features),