The current situation of the Gstreamer detection does not always honor
all the configurations set by the user, among this:
- if both WITH_GSTREAMER and WITH_GSTREAMER_0_10 are off, but
  Gstreamer 0.10 is installed in the system, Gstreamer 0.10 support will
  be enable;
- if both WITH_GSTREAMER and WITH_GSTREAMER_0_10 are on, only checks for
  Gstreamer 0.10 will be run.

This patch fixes the Gstreamer detection like this:

  |        -DWITH_...          | Package installed  ||    OpenCV    |
  | GSTREAMER | GSTREAMER_0_10 | gst-1.x | gst-0.10 || gst. support |
  +===========+================+=========+==========##==============+
  |    OFF    |      OFF       |    -    |    -     ||     none     |
  |    OFF    |      ON        |    -    |    no    ||     none     |
  |    OFF    |      ON        |    -    |   yes    ||   gst-0.10   |
  |    ON     |      OFF       |    no   |    no    ||     none     |
  |    ON     |      OFF       |    no   |   yes    ||   gst-0.10   |
  |    ON     |      OFF       |   yes   |    -     ||    gst-1.x   |
  |    ON     |      ON        |   yes   |    -     ||    gst-1.x   |
Signed-off-by: Samuel Martin <s.martin49@gmail.com>

Use _com_ptr_t instead of CComPtr in ComPtr wrapper to avoid ATL dependency.

The Mutex manager registered with ffmpeg must reset the mutex to NULL after destruction, otherwise ffmpeg will give the invalid mutex to the next mutex manager when it asks it to CREATE a new mutex.
See ffmpeg code: http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/utils.c;h=28c5785398fcf11a3d3c70a8cd09e9df798e2734;hb=HEAD#l3423

Cherry picked from head (file has moved but issue is the same).
Conflicts:
	modules/videoio/src/cap_ffmpeg_impl.hpp

Currently, FFMPEG source files are included in highgui project file regardless of CMake WITH_FFMPEG option.
After applying this PR FFMPEG files are included only if WITH_FFMPEG option is enabled.

Taken from 3f076552