Feature/Python interface via ctypes

[jlnav]

• [x] Add CI test/build, and to make check
• [x] Ensure libnrm can be located
• [ ] Documentation
• [x] Remaining client features (implement wrapper-classes for Actuators, Sensors, etc.)
• [ ] Register Python callbacks eventually
• [ ] Test everything

[perarnau]

Quick note about a better way to do restype and error checking. There's a way to setup an error checking function: https://docs.python.org/3/library/ctypes.html#ctypes._FuncPtr.errcheck