Update submodule ecl to latest Wed Oct 3 02:37:29 EDT 2018

    - ecl in PX4/Firmware (f56b8f8): PX4/PX4-ECL@2354c30
    - ecl current upstream: PX4/PX4-ECL@2c3a064
    - Changes: PX4/PX4-ECL@2354c30...2c3a064

    2c3a064 2018-09-18 Daniel Agar - README.md update Jenkins build status icon and url
f240eaa 2018-09-18 Paul Riseborough - EKF: Fix test script
5cb228e 2018-09-18 Paul Riseborough - EKF: Remove duplicate line
0220f46 2018-09-18 Paul Riseborough - EKF: Use more generic variable name for bad yaw fusion flag
eb52f7c 2018-09-03 Paul Riseborough - EKF: Remove implicit conversion and use single precision trig operator
6847acb 2018-09-02 Paul Riseborough - EKF: Add protection for undefined GPS antenna array heading offset
d1f3f4c 2018-09-02 Paul Riseborough - EKF: Use #define function for isfinite check
91f886c 2018-08-28 Paul Riseborough - EKF: Add support for use of GPS heading data.
af60e6b 2018-08-28 Paul Riseborough - EKF: Add derivation for for dual antenna yaw observations
342c3ab 2018-08-28 Paul Riseborough - EKF: Fix timeout parameter documentation and name