feat($grab-one): start of solid frame color detection  #1

If near-black is detected on most pixels, move forward 5 frames and try again.

Many new TODOs in the code related to this.  Also:
- It's probably time to start splitting up the code into files

- Unit tests for the solid color detection would be nice.  Maybe we can progamatically setup some canvases for the tests with varying color ranges.  This will likely help refine the solid color detection algorithm, which I am a bit uncertain about at the moment.