Large Display: x by y w/ 24 bpp Graphics buffer visualized with neopixel string in zig-zag layout

Hopefully I won't start hurling abuse at contributors :)

edit: I do really appreciate any contributions to Espruino. However, I do this full time and I'm aware that in a lot of cases (like with the Neopixels) I have a lot of hardware available here that I can test with - its not reasonable to expect others that are suggesting changes to have tested on all the same stuff, so at the end of the day it falls down to me to test things out before merging.