Minor updates to make use of new functionality in microbit-dal that performs
autodetection of attached sensors and instatiation of drivers. Also some code
cleanups to remove unused code.
More specifically:
- Changed MicroBitAccelerometer and MicroBitCompass objects to be references.
This is to support dynamic autodetection and instantiation of drivers for such hardware.
- Updates to initialise MicroBitAccelerometer and MicroBitCompass references
through the MicroBitAccelerometer::autoDetect() and MicroBitCompass::autoDetect() methods, respectively.
- Add storage object to MicroBitCompassCalibrator constructor to enable
persistent storing of calibration data.
- Updated use of accelerometer updateSample() to more commonly used getSample()
method to improve clarity and to provide a reference example.
- Exposed sensor IRQ lines via MicroBitIO.
- Removed redundant include of Matrix4.h