Also deleted miscellaneous remaining multimon cruft.
Deleted #include <winuser.h>, because <windows.h> includes it
already.

This should have a nice side effect of preventing us from
accidentally using any Windows API that's too new.

avformat_find_stream_info was introduced in Libav avformat 53.3,
but it was only merged to FFmpeg in avformat 53.6.

In Libav avformat 53.3-53.5 av_find_stream_info is not removed
(only deprecated), so this shouldn't break building with that.

Searching in directory names can yield confusing results; e.g. if
the input is "jpeg2000/image1.jp2", it will infer the pattern
"jpeg%04d/image1.jp2", which is likely not what the user intended.

If the user really desires for the variable part to be in the
directory name, it can always use an explicit pattern.

at can't be a null pointer, so the condition was always false, and
a nonsensical pattern like "image.png%00d" was being inferred.

  - crosses initializations in "cap_ximea.cpp" (which also contained some awfull "goto" instructions)
  - the "CMAKE_CL_64" variable is not initialized when using mingw

PR#1039 modified to be able to merge on branch 2.4

CvCaptureFile::grabFrame() always returns 1 regardless, which causes
dead loop when relying on the return value of VideoCapture::read().

Previously, VideoCapture::retrieve would return a Mat that referenced
the internal IplImage. Since the latter is rewritten every time a
frame is captured, it means that if the user captures two frames in a row,
the first frame would reference nothing. Similar if a user captures a frame,
then destroys the VideoCapture instance.

Note that the other branch of the if isn't affected, since flip allocates
a new Mat.

From commit dd74a851, to be exact. Now cap_ffmpeg.cpp should actually
build if HAVE_FFMPEG is true.

Also modified some gpu sources in a similar manner.

we doesn't create OpenGL windows by default
OpenGL window must be created by user via namedWindow

QVector range check exception fixed.

We never set it, and libdc1394 0.9.5 is obsolete anyway - 1.0 came out
in 2004.

Note that 1.0 doesn't have the do_extra_buffering parameter.

This reverts commit 41b8479d, reversing
changes made to 531471b0.

Reason: breaks the build.

libpng 1.5+ recommends a call to png_set_interlace_handling() if you use
png_read_update_info and png_read_image. It will generate a warning
without it.

Also removed malformed tEXt chunk from a logo PNG.

Correct reading PNG color type palette with or without alpha imread flags -1 or 1
Better not using pnginfo.h, using png_get_tRNS instead

for libpng added.

VideoWriter memory leak solved.