Initial commit of the C-API driver code, built on top of simple_message code.
Every file from simple_message can be found in the respective directory.
Most files have a simple change added, an ifdef for the FLAT_HEADER symbol,
which removes the global addressing ROS creates for header lookup.
Later versions should remove the MOTOPLUS symbol from most of these files
and simply define both symbols.
Code which needs to be Universal specific was added with the
UNIVERSAL ifdef symbol.
Test files test_com.cpp and mp_main.cpp were also created for sandbox testing.