p5js/friezes - Add new transformation to flip horizontally
p5js/friezes - Add new transformation to flip horizontally

* This allows the "horizontal flip" transformation to be used within the set of transformations between each tile.

Note:
- When combined with the existing `this.drawHorizReflection()` it produces interesting (albeit unintentional) translation of the pattern.

brianhonohan/sketchbook,brianhonohan/sketchbook,brianhonohan/sketchbook