Video input, ARDrone2 bringup

For some reason we neglected to merge the work on the video stream we did a while back. This pull request includes those commits, along with a commit which adds rudimentary support for the ARDrone2.
Navigation seems to work okay, we are just lacking video as the new ARDrone uses the H264 codec as opposed to their P264 codec. On the one hand at least it now uses a standard codec, on the other this means we'll have to write a H264 codec or use something like ffmpeg to decode it.