Update submodule ecl to latest Wed Sep 4 08:37:31 EDT 2019

    - ecl in PX4/Firmware (da69703): PX4/PX4-ECL@62fa464
    - ecl current upstream: PX4/PX4-ECL@3b32ee4
    - Changes: PX4/PX4-ECL@62fa464...3b32ee4

    3b32ee4 2019-09-02 bresch - Flow aiding - Reset state when flow is enabled only if it is the only position/velocity aiding sensor. Until now, it was alway resetting if the vehicle does not have gps or external vision. This caused a reset/glitch at every stop (when range data gets valid)
be368f3 2019-08-28 kamilritz - Update comment
c5abfe6 2019-08-28 kamilritz - remove canonicalize and adapt comments
67512d8 2019-08-22 kamilritz - Update matrix library for CI
a2ff415 2019-08-22 kamilritz - Fix get frame aligning quaternion function
53eac6e 2019-08-21 kamilritz - Canonicalize alignment quaternion
933c32c 2019-08-20 kamilritz - Enable local frame alignment also without using it
ea352a6 2019-08-20 kamilritz - Dont use mag suffix for magnitude
05196db 2019-08-20 kamilritz - Fix alignment of local frame