Update submodule sitl_gazebo to latest Fri Oct 25 12:40:00 UTC 2019
Update submodule sitl_gazebo to latest Fri Oct 25 12:40:00 UTC 2019

    - sitl_gazebo in PX4/Firmware (ffefd458bece711bc8862fe23eeda7280aad3c5f): https://github.com/PX4/sitl_gazebo/commit/c0634b241eb730cee2ef91e5f5298427a4a328c8
    - sitl_gazebo current upstream: https://github.com/PX4/sitl_gazebo/commit/169d48217df89922e9fae72ef34fa46ce2e209dd
    - Changes: https://github.com/PX4/sitl_gazebo/compare/c0634b241eb730cee2ef91e5f5298427a4a328c8...169d48217df89922e9fae72ef34fa46ce2e209dd

    169d482 2019-10-22 Julian Oes - travis: let's not bother about macOS Sierra
78fef51 2019-10-22 Julian Oes - travis: install gstreamer using brew
764d1b7 2019-10-21 Julian Oes - models: fix reported validation errors
053622b 2019-10-11 TSC21 - Travis CI: Cleanup scripts and add more MacOSX build pipelines
0c8214c 2019-10-21 Julian Oes - cmake: fix Qt prefix path for macOS
bb2c08c 2019-10-06 TSC21 - CMake: fix Qt5 find in MacOS
81f072b 2019-10-14 Julian Oes - travis: install GStreamer using brew
39d4399 2019-10-14 Julian Oes - cmake: link to glib-2.0 and gobject-2.0
fef3ff5 2019-10-14 Julian Oes - cmake: fix GStreamer and Qt deps for macOS
605da22 2019-10-22 Nuno Marques - Update README.md
2a8a54e 2019-10-20 Nuno Marques - README: update install instructions

PX4/Firmware,acfloria/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,acfloria/Firmware,PX4/Firmware,krbeverx/Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware,PX4/Firmware,acfloria/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,krbeverx/Firmware,PX4/Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware