make_frame_tile.py reads the release tile from the git-ignored
assets/background, takes the Quest help off it, draws the Frame's, and
writes it into build/frame-assets. The frame build type's assets override
the release tile with it, a gradle task runs it before mergeFrameAssets.
Quest and Pico builds are untouched. If the tile or Pillow and numpy are
missing, the Frame build goes on with the release tile and a warning.
