work-around for https://github.com/PX4/Firmware/issues/9461

Both IO and FMU are connected to the safety switch for default models. This needs later to be broken out to a config option for builds that do not contain an IO.

Subsystem_info status flags & checks: Add comment to indicate that the IMU+MAG consistency checks need to be performed AFTER the individual checks are complete

Subsystem_info status flags & checks: Suppress sensor failover warnings in Hardware in the loop (HITL)

Subsystem_info status flags & checks: Moved the set_health_flags helper functions out of the /lib/ folder and into the module/commander folder because they are actually only needed there

Subsystem_info status flags & checks: Code style fixes and cleanup to avoid strcmp() as suggested by @LorenzMeier

Subsystem_info status flags & checks: Separate the functionality to a) set the health flags inside commander and b) to publish them from external modules

Remove distance sensor checks again. These checks should be handled by EKF2 and should thus be added there later

vl53lxx distance sensor: Remove subsystem_info calls because all sensors are now checked inside commander

Subsystem_info status flags & checks: 1) Set health flags in commander directly instead of publishing via uORB 2) move publish_subsystem_info into lib/ folder"

Subsystem_info status flags & checks: Switch back to uORB for inter-process communication, handle GPS checks completely inside ekf2, add distance_sensor checks

Subsystem_info status flags & checks : Initial commit, updating the health flags in a centralized way mostly in commander and the votedSensorsUpdate function.

to disable automatic evaluation of /dev/ttyS* expression in cygwin.
On linux verbatim seems to be default anyways. At least it doesn't get
evaluated on linux.

fw_att_control: Fix bug that caused the rudder to stutter when FW_RLL_TO_YAW_FF>0 and aileron input was supplied

    - sitl_gazebo in PX4/Firmware (bbc104ad): https://github.com/PX4/sitl_gazebo/commit/371e7c36c34d7dd45da5602a14a6ee01e9fe74db
    - sitl_gazebo current upstream: https://github.com/PX4/sitl_gazebo/commit/e8b3624b9dad63a492ae58c1ce8661488128966b
    - Changes: https://github.com/PX4/sitl_gazebo/compare/371e7c36c34d7dd45da5602a14a6ee01e9fe74db...e8b3624b9dad63a492ae58c1ce8661488128966b

    e8b3624 2018-06-04 Elia Tarasov - tune gimbal pid gains
54c256d 2018-06-05 Poutshi - Update README.md (#211)
1992b0d 2018-06-05 TSC21 - CMakeLists: fix targe msg links
10b0597 2018-06-01 TSC21 - validade_sdf: fix typo
8fee88e 2018-06-01 TSC21 - travis_ci: add catkin build
de983cc 2018-05-31 TSC21 - generate separate protobuff libs for each msg category
6cb9360 2018-05-31 TSC21 - restructure proto msg API (rename, organize list)
5a250a2 2018-05-31 TSC21 - proto msgs: use PascalCase convention
ea6e2da 2018-05-31 TSC21 - remove the rotors_ prefix from plugin names
7989043 2018-05-31 TSC21 - allow building with the most recent C++ compiler available on the host
b819817 2018-05-31 TSC21 - package.xml: update and reorganize package list
a20bf63 2018-05-31 TSC21 - CMakeLists: reorganize build target and dependecies list
ae7df80 2018-05-31 TSC21 - CMakeLists: remove exception for ROS when building gazebo_geotagged_images_plugin (no longer applicable)
0a4e27b 2018-05-31 TSC21 - CMakeLists: fix typo on building gazebo_motor_failure_plugin
27f977b 2018-05-31 TSC21 - gazebo_mavlink_interface: add support for Gazebo 9 for model_param func
eded9b2 2018-05-31 Elia Tarasov - set default pid gains as constants
29b5424 2018-05-31 Elia Tarasov - add default pid control gains to sdf xml
4caf496 2018-05-30 Elia Tarasov - move pid control gains to sdf xml

fix rgbled On and Powersave value in read mode.
In read mode, the ENABLE and SHDN is in bit 4 and bit5, so we may need a 4bit left shift to get a correct value.

Fixes the following corner case:
mpu9250 start -R
This would return a valid result (myoptind < argc), but myoptind pointed
to a NULL argument (and thus mpu9250 would crash).
With this patch, px4_getopt will return '?', indicating a parser error.