Devel

- AttitudeESKF accepts matrices for covariance parameters, instead of assuming diagonal noise.
- Noise parameters are not provided by `rosparam` anymore, and are expected to arrive in the incoming messages.
- Process model treats gyro covariance with the correct units (rad/s)^2 instead of (rad)^2.
- Magnetic bias/scale/reference vectors are loaded as lists instead of key-value arrays.
- Magnetometer calibration now uses least squares for initial guess, and LM iteration is robustified with Cauchy weighting.
- Calibration is triggered by a callable ROS service, instead of from the launch file options.
- Added support for `diagnostic_updater`.
- Renamed `adjusted_field` topic to `corrected_field`.
- Refactored ROS code into a Node class.
- Removed `broadcast_frame` option and `tf`-dependent code.
- Pose is always published.