Update submodule ecl to latest Sun Feb 3 07:37:55 EST 2019

    - ecl in PX4/Firmware (0dc2ccb130e891b387b4e0d6ea4492473339e142): https://github.com/PX4/ecl/commit/721f5e61a5965a08a34b2875d2bdc0b5d3b80601
    - ecl current upstream: https://github.com/PX4/ecl/commit/dd58e695494acab73fb6fcec7074291edb5c226b
    - Changes: https://github.com/PX4/ecl/compare/721f5e61a5965a08a34b2875d2bdc0b5d3b80601...dd58e695494acab73fb6fcec7074291edb5c226b

    dd58e69 2019-01-30 Paul Riseborough - EKF: Ensure FW yaw alignment method is used on first in-air reset
3accab1 2019-01-28 Paul Riseborough - EKF: protect declination fusion from badly conditioned earth field estimates
7bddbd1 2019-01-28 Paul Riseborough - EKF: Update cleaned up autocode fragment with sign error fix and missing LD
fe378fd 2019-01-22 Paul Riseborough - EKF: Prevent unwanted declination fusion when re-starting 3-axis fusion
bd1647a 2019-01-22 Paul Riseborough - EKF: Rework use of fuseDeclination()
d52f536 2019-01-17 Paul Riseborough - EKF: Save mag field covariance data before reset
82ce7a8 2019-01-17 Paul Riseborough - EKF: Save mag field covariance information on startup
708c79e 2019-01-17 Paul Riseborough - EKF: Ensure mag field state covariance data is always available for re-use
8839e4e 2019-01-17 Paul Riseborough - EKF: Don't discard declination certainty information when resuming 3-axis fusion.
25148e1 2019-01-17 Paul Riseborough - EKF: Prevent rapid changes in declination estimate after a reset
6e7c119 2019-01-16 CarlOlsson - EKF: limit yaw variance increase to 0.01 rad^2 to prevent a badly conditioned covariance matrix
0896f7b 2019-01-16 CarlOlsson - EKF: Also fill in lower part of covariance matrix in increaseQuatYawErrVariance()
4b3140e 2019-01-16 Paul Riseborough - EKF: Fix rebase error
911d4d8 2019-01-16 Paul Riseborough - EKF: Fix sign error in increaseQuatYawErrVariance function
a0b9cb0 2018-12-24 Paul Riseborough - EKF: Use consistent method for recording completion of in-flight yaw alignment
ef5a87c 2018-12-21 Paul Riseborough - EKF: Rework quaternion yaw reset.
fc2a089 2018-12-21 Paul Riseborough - EKF: Add function to un-correlate quaternion states
bce1b96 2018-12-21 Paul Riseborough - EKF: Add function enabling yaw variance to be increased
bf1f3a2 2018-12-21 Paul Riseborough - EKF: Derive equations enabling yaw variance to be increased
81eabc1 2019-01-29 Daniel Agar - Jenkins update all containers to latest tag 2019-01-28
a5e6191 2019-01-29 Daniel Agar - EKF add clarity brackets to avoid potential confusion

ecl @ dd58e695

-Subproject commit 721f5e61a5965a08a34b2875d2bdc0b5d3b80601
+Subproject commit dd58e695494acab73fb6fcec7074291edb5c226b