bno055: Clean up and fix

[auscompgeek]

Apparently our BNO055.getHeadingRate() has been broken this entire time.
We also had roll and pitch the wrong way around according to the
datasheet, but at least we weren't reading those anyway.

[codecov]

Codecov Report

Merging #27 into master will increase coverage by 0.21%.
The diff coverage is 94.73%.

@@            Coverage Diff             @@
##           master      #27      +/-   ##
==========================================
+ Coverage    82.6%   82.81%   +0.21%     
==========================================
  Files          19       19              
  Lines        1604     1618      +14     
  Branches      168      165       -3     
==========================================
+ Hits         1325     1340      +15     
  Misses        228      228              
+ Partials       51       50       -1

Impacted Files	Coverage Δ
utilities/bno055_sim.py	89.47% <100%> (ø)	⬆️
utilities/bno055.py	94.21% <94.52%> (+0.79%)	⬆️

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[james-ward]

Surely the yaw rate is around the z-axis?

[auscompgeek]

IIRC, the BNO055 data sheet defines the X axis as the heading/yaw. I'll double-check again, but given the order of the registers, it makes sense.