This branch fixes a reported bug, fixes tow potential bugs and fixes a minor documentation error.
1) Removes code un-used under normal conditions that would prevent a height reset if a negative height variance was present. Potential bug.
2) Fix error in parameter documentation.
3) Adds missing initialisations for class variables . Potential bug.
4) Prevents the EKF loss of navigation message being output on startup. Reported bug.
Make it clearer that the gate parameters control innovation consistency checks and that the gate size is specified in standard deviations.
Also make it clear that the EKF2_BARO_GATE also controls the GPS height fusion.
* msg: add reporting of multi rotor drag fusion
* ekf2: add reporting of multi rotor drag fusion
* ekf2: Add parameters required to tune multi-rotor wind estimation
* ekf2: Add correction for static pressure position error
* ekf2: Use correct air density for position error corrections
* ekf2: fix parameter documentation error
* ekf2: Add separate forward and reverse position error correction factors
* ekf2: Fix formatting and parameter descriptions
* ekf2: Improve comments
Paul Riseborough