OP-1139: perform second order low temperature compensation.
It follows the procedure described in MS5611 datasheet(http://www.meas-spec.com/downloads/MS5611-01BA03.pdf, page 8)
to perform low(20°) and very low(-15°C) temperature compensation.
OP.1139: uncrustify
OP-1141: allow to input a barometer bias model.
It uses a 3rd degree polynomial to model pressure bias as a function of temperature.
OP-1139: export corrected pressure value to uavobject
OP-1139: Add some more descriptive names and comments for compensation variables
OP-1139: missing uncrustification
Merge remote-tracking branch 'origin/amorale/OP-1139_baro_2nd_order_compensation' into corvuscorax/OP-1022_AH_improvements_amorale
changed defaults for altitude hold control loop coefficients