Add calibration parameters for IMU data

[aburt2]

Added calibration parameters for the IMU data for Sensor fusion. Based on the calibration parameters from https://github.com/xioTechnologies/Fusion.

• adds gyro and accelerometer offset (only does offset calibration, does not include misalignment or sensitivity matrix)
• adds parameters for both soft and hard iron magnetometer calibration
• adds three methods calibrateAccelerometer, calibrateMagnetometer and calibrateGyroscope for calibrating the values sent to the sensor fusion algorithm
• Does not calibrate the sensors only computes the calibrated values given the calibration parameters

[aburt2]

@edumeneses forgot I had finished this a while ago

[edumeneses]

Great. Thanks for that.

Please keep in mind that the refactor will probably break a lot of things.

I will make a release before refactoring to ensure compatibility with old firmware.

[aburt2]

Thanks @edumeneses can you merge it, I don't have access to merge for this repo