Add option to run in low-res mode
This means an additional Message Action type for MT_STREAM: MA_START_LOW.
This implies the following:
- handleStream: adds msgAction case for MA_START_LOW that is the same as MA_START, but passes the msgAction value to spawnStream.
- spawnStream: accepts msgAction type argument.
- spawnStream: uses msgAction argument to select the FPS and builds command with that.
If I do this then I can use the media system as a web cam at the house, using an ssh tunnel to the Pi's. Using the phone at 30fps works but is really, really slow and falls behind quickly. I think slowing down the frame rate (and maybe the video size) would help.