Reimplement and refactor the display driver code

[joukos]

The current drivers are essentially exactly the same as the reference drivers - they leave a lot to be desired:

• the frame buffer handling / drawing / bit fiddling is done in an unnecessarily convoluted fashion - they could be made much simpler and more readable
• the repetition in the display commands etc. is quite dull and redundant - many parts of the drivers could be reduced to more readable oneliners
• there are confusing comments, non-pythonic code, varying naming schemes and code that makes one wonder if it works correctly or not
• etc.

Having more knowledge of the particulars of these displays (and the actual hardware available for testing!) should yield a rewrite that is much simpler and nice to read.

Pull requests / issues are very welcome.