argv[1] was read even if argc < 2 -> segmentation fault when running without arguments
the return saves this

According to https://github.com/mavlink/mavlink/pull/629 the mavlink
command DO_SET_MODE should only determine the mode but not the
armed/disarmed state, so the MAV_MODE_FLAG_SAFETY_ARMED bit should be
ignored.
Instead the mavlink command COMPONENT_ARM_DISARM should be used instead.

Therefore, the commander now ignores the arm/disarm bit.

fix code style

roughly 10K bytes below the 1MiB limit

note that FMU does not update AUX pwm outputs if no RC signal

clamp mixer output offset to [-.2,.2] ([-2000, 2000] in mixer file)

add 8 main PWM trim parameters

add long desc to parameters and bump minor parameter version

Implement the way to run posix simulator directly from IDE without the need to reconfigure command lines, but use runner created via CMake

Steps to debug:
 * Run gazebo (or any other sim) server and client viewers via the terminal: `make posix_sitl_default gazebo_none_ide`
 * In your IDE select `px4_<mode>` target you want to debug (e.g. `px4_iris`)
 * Start debug session directly from IDE

This approach significantly reduces the debug cycle time because simulator (e.g. gazebo) is always running in background and you only re-run px4 process which is very light.

This also adds a ZMR250 config.