Support more resolutions

Now find the smallest resolution available that is still greater than
1280x720.

Resolutions that aren't exactly 1280x720 are still slightly broken
because they don't scale or center.
Merge branch 'master' of github.com:limelight-stream/limelight-pc

* 'master' of github.com:limelight-stream/limelight-pc:
  Drop audio samples if buffer space is not available to preserve real-time audio behavior