todo

LCD module driver

 - implement more modes, i.e. double hight characters, other cursors,...
 - I am unsure about the way I have done the needed delays. The LCD modules
   are very picky about them, i.e. data may in no case be sent too fast to
   it or you'll loose it. Currently the delays are done using the udelay()
   kernel function. AFAIK this does busy waiting but I do not know exactly.
   If anyone has a better way PLEASE let me know!
 - Implement some way to have buttons attached to the display module to do
   some controls. I plan to add an interrupt handler to the driver and use
   the four still unused input lines of the parallel port for 7 buttons and
   one interrupt line. Any help welcome!