It is working now.

To be fixed:
 * There is some dirty stuff going on inside the AVR ISR.
 * For ease of debugging the config is stored and sent in plain text,
   the LZMA stuff needs to be uncommented.
 * Quite probably one or two more ugly hacks, the whole thing should be
   reviewed.
Modified the pylibcerebrum package layout
Fixed a bug breaking transmission of buffers from the device

...and removed debug output in pylibcerebrum.