Exposure control not available on Mac

[TheMariday]

Also had trouble on a Mac with multiple webcams. Using my iPhone with free version of Camo Studio app worked pretty well

Originally posted by @JohnnyMarnell in #33 (comment)

On a mac, I was unable to get any camera with exposure control working, even supported webcams. I used a 3rd party tool called "webcam settings" to drop exposure way way down until the preview mode started looking right. The app is kind of hit or miss, and only 2 star rating so I can't really recommend it.

Got me thinking, would a diff exposure mode be possible, where it could work with auto exposure and mostly bright frames? Like take a picture with no LEDs, light an LED, subtract the first frame from the second.

Originally posted by @simap in #33 (comment)

[TheMariday]

So it looks like opencv can only control format, width and height of webcams on mac. source

Well that solves it, sadly in that case this becomes an unfixable issue.

Documentation update required.