creating new package for imu_compass
added imu_compass.cpp, used to be called um6_compass when it came from https://github.com/clearpathrobotics/um6/tree/compass_cleanup/src
added imu_compass as a target
removed references to um6
clean up CMakeLists and add header file to clean up compass code
moved class definition to header file
added launch files and script to compute magnetometer calibration parameters from a bag file, added param file to hold said parameters, CMakelist modifications to boot