Improve macOS capture performance

[BradyBrenot]

screen_capture_lite is using CGDisplayCreateImage, which does not appear to be intended for repeated capture of the screen but rather for one-off screen grabs. It's killing the OS; WindowServer spikes up to 90%+ CPU use and everything slows down.

Better methods:

• How to capture screen activity to a movie file using AV Foundation on OS X 10.7 Lion and later
• OpenGLCaptureToMovie

[BradyBrenot]

Calling this until I get reports that it's still crap on modern Macs