Pixel Matrix format is inefficient

[pzich]

asciify-pixel-matrix uses a pixel matrix in the following format:

[
  [{r: 255, g: 255, b: 255, a: 1}, {r: 255, g: 255, b: 255, a: 1}, ...],
  [{r: 255, g: 255, b: 255, a: 1}, {r: 255, g: 255, b: 255, a: 1}, ...],
  ...
]

This is very inefficient compared to the Buffer of bytes it already comes in as from ffmpeg, and all it does is immediately pull these values out to call asciify-pixel on each one. I suspect there will be a major performance improvement by bypassing this format and using something more efficient.