-add support for setting / getting the number of read buffers

-add code to v4l2_read to not return frames more then say 5 seconds old

-add support for libv4l1 for non pure capture (combined capture and overlay)
 devices so that atleast CGMBUF emulation (but no conversion, as thats
 impossible for overlays) can be done, so that it will no longer be
 necessary to implement CGMBUF in the kernel for each driver.

-take the possibility of pitch != width into account everywhere

-make updating of parameters happen based on time elapsed rather then
 frames

-get standardized CID for AUTOGAIN_TARGET upstream and switch to that
