Get the keymaps right

This gave me some good headache. I couldn't by hell get the right scan codes
out of the keyboard until I realised that my host Linux already sends
translated codes to qemu. Now the Makefile contains the switch -k de to let
qemu know that it has to treat its input as originating from the german
keyboard layout I indeed use. Now, the correct codes arrive in the emulator.

The code is not useful at the moment. It prints out a lot of stuff to help
me fine-tuning the keymaps. e0 and e1 sequences are still be to implemented
as most of the other work is.