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

The matrix g  can have CV_32F or CV_64F type,  but g.at uses only float template.
This fix adds specialization for double type.

Revise some descriptions of the enums.

Add a new variant of detectMultiScale with output arguments 'objects' and 'numDetections'; factor most of detectMultiScale's code into 2 protected methods

Python 3 requires METH_VARARGS | METH_KEYWORDS, not just METH_KEYWORDS.

In these cases, just using print() is enough to ensure py2/3
compatibility.

Added a header with defines to enable the module to compile with either
python 2 or 3 without changes.

Merged android.toolchain.cmake from project
https://github.com/taka-no-me/android-cmake
commit: fd1f7055f8b7338644d58d9a2015a784dfa3a5ca

OPENCLAMDBLAS and OPENCLAMDFFT never detected under linux.
lib64/import and lib32/import is the path on Windows but not Linux.
for CLAMDBLAS library we should use CLAMDBLAS_PATH (not CLAMDFFT_PATH)