[ANN] Added streaming tests for v4l2-compliance

[Hans Verkuil <hverkuil@xs4all.nl>]

Hi all,

I've just committed and pushed my latest changes to v4l2-compliance. It adds
initial support for testing the I/O streaming ioctls. It's currently limited
to standard VIDEO_CAPTURE, so no output, m2m or multiplanar support.

You need to add the -s flag in order to test this, and you may have to set the
correct input and frequency as well since the streaming tests assume you have
a proper video signal on the input.

It already found this regression:

http://www.spinics.net/lists/linux-media/msg72824.html

So any driver that supports VIDIOC_PREPARE_BUF will have to apply that patch
first, otherwise it will definitely fail to work.

By no means am I doing full coverage testing, but at least the main things
are now covered.

Particularly tests for nasty things (wrong pointers, buffers too small, closing
filehandles mid-streaming, stuff like that) need to be added. That's never tested
normally so stress tests like that will be very useful.

Feedback and ideas are welcome!

Regards,

	Hans