Improved the screen consumer
============================
* No longer spin waits for vsync (the video card driver seems to do this at
least with nvidia), but sleeps almost up until the time when the vertical
blank occurs, thus the time for swap buffers (a smaller spin wait than
before).
* Now deinterlaces to two separate frames so for example 50i will no longer
be converted to 25p but instead to 50p for smooth playback of interlaced
content.
git-svn-id: https://casparcg.svn.sourceforge.net/svnroot/casparcg/server/trunk@3205
362d55ac-95cf-4e76-9f9a-
cbaa9c17b72d