Abstract functions are closer to the top
because they must be implemented and documentation
should be near the top.
Important virtual functions moved up too.
Additional documentation added and existing adapted
to 80 column width.
I tried to reduce the number of included files and sorted them a bit
1. Interface functions moved closer to top (and functions which should
be implemented)
2. ioBoardAddress renamed to logicalAddress. getter FUnction added.
3. debug interface for easier debugging of device handlers
4. new documentation
5. new return value for scanForReply to ignore full packet
