(cherry picked from commit 2b2e3ee9)

Conflicts:
	cmake/OpenCVFindLibsVideo.cmake
	modules/videoio/src/cap.cpp
	modules/videoio/src/cap_ffmpeg_impl.hpp
	modules/videoio/src/ffmpeg_codecs.hpp
	modules/videoio/test/test_ffmpeg.cpp

Useless output to console fixed;
Test output files moved from cwd to temp folder.
(cherry picked from commit 87935f35)

Useless output to console fixed;
Test output files moved from cwd to temp folder.

Our prebuilt FFmpeg Windows binaries don't have PNG support enabled
(because that requires zlib), so that makes a PNG image a bad choice
for this test.

When FFmpeg doesn't support PNG, VideoCapture falls back to the
"image sequence" implementation, which doesn't work for single images.

Newer FFmpeg prohibits 4096x4096 MPEG-2, presumably because it violates
the standard.

http://git.videolan.org/gitweb.cgi/ffmpeg.git/?p=ffmpeg.git;a=commit;h=7fb87bc5f24b1be13269109506c05e4c54695b5e

(cherry picked from commit 424a7b0a)

Conflicts:
	modules/highgui/test/test_ffmpeg.cpp

(cherry picked from commit 3f3ae333)

added explicit VideoWriter::release(). Fixed video stream finalization (write remaining frames); Fixed occasional crash in the case of odd-width or odd-height videos; Fixed a few problems in ffmpeg tests. Positioning still does not work well.

reduced the video size in video writer tests; retained only most popular codecs. added ffmpeg support on MacOSX.

added COVAR_ and SORT_ enums to core.hpp; fixed many, many VS2005, VS2010 and MinGW (GCC 4.5.2) warnings

reworked nearly all of the OpenCV tests (except for opencv_gpu tests) - they now use the Google Test engine.