Implement a command to cause a running mavid instance to stop recording

[morgant]

Currently, since mavid uses two piped ffmpeg processes (one for audio, the other for video and muxing), one can't just press q to stop recording in ffmpeg and so must press ctrl-c. This is fine, and documented, but I'd love to be able to run mavid from a hot key or menu in my X11 window manager (WM; much like I do for maim in mlvwmrc-screenshot), so we'd need a way to inform the original mavid process that it should stop recording.

My initial thought is, if after implementing issues #1 & #2, that we could ad an option that just sends a signal to the process of an already running maim instance, causing it to stop recording.