Added a number of units as discussed with Nick.
Remove unit for RMS g.
Fix and improve units for flow (mass/volume).
Various improvements to units for volume.
Various improvements to units for flow (volume).
Various improvements to units for torque.
Various improvements to units for mass.
Don't prevent flake8 from checking entire file.
Various improvements to units for energy.
Various improvements to units for length.
Various improvements to units for pressure.
Various improvements to units for density.
Minor tidying to units.
Merge branch 'master' of github.com:FlightDataServices/FlightDataUtilities