Add Resilient Packet Ring Interface and Node class.
Tested and it works, but not safe.
Initial commit of simple logger based on Georgis idea.
Baud rate increased to 3Mbaud, single channel plotter works.
Restructured Monitor
Very slow FIR filter. Fixed-point scaling is not done in the right way.
Fix ADC pullups
FIR-Filter: Created unit tests for FIR filter implementation.

Right now only a "delay line" filter test with handcoded values
is available.
TODO: Add coefficients, taps and results for filters calculated
with octave or scipy etc.
FIR-Filter: rudimentary construct added. TODO: implement filter
FIR: implemented filtering function with loop unroling.

Some further tests and optimizations are needed though.
Merge branch 'develop' into feature/fast_logger
FIR: New buffering scheme. Added debug functions.

The FIR filter now implements a buffering scheme that avoids
shifting the tap buffer every time a new value is appended.
The filter now only needs to shift every BLOCK_SIZE+1 times.
The tradeoff is that it uses BLOCK_SIZE additional memory.

DEBUG: Some debugging defines have been added in fir_impl.hpp
They allow to prinf memory when running unit tests on a PC.
Right now this is implemented by checking whether DEBUG is defined.
This should be improved to automatically detect unit test builds.
FIR: Added ScaleFactor to enable fixed point math.
FIR: Replaced DEBUG define with FIR_DEBUG to prevent errors.
Merge branch 'develop' into feature/fast_logger
FIR: Scale Factor now used to scale down output
Fix issue where messages were accepted at too small length.
Merge branch 'develop' into feature/resilient_packet_ring
Fix inline use in Atmega SPI.
Remove unnecessary header guards from rpr.hpp file.
Add HMC6343 driver.