Added genReDisplay()

Added a function which deletes the current display and replaces it
rather than just reshowing it. I think it's nicer.
To do this I did stuff like add a \b character to the end of the display
bytes which is utilised by this function, and that charString() function
I talked about adding which just generates a nice-to-look-at string of a
given character.

Again, I still don't know if the bf code actually works.