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.

With GCC 4.9 the binary is to large for the flash memory.
This is why we disabled LPE on that platform.

We propagate the bus parameters from the bus interface to the sensor
devices. Thus, the device ID of the sensor driver is set to the correct
bus id and address. Otherwise it would be zero, which is an issue if several MPU9250s
are running at the same time.

This fixes the following corner case:
1. Upload a mission.
2. Set mission mode.
3. Set loiter mode.
4. Arm.
At this point it will shoot up and go to the takeoff waypoint even
though we're not in mission but in loiter mode.

The fix makes sure that the triplet is reset to invalid (and idle) in
loiter mode if we're landed and disarmed.
It will lead to the vehcle sit in idle on the ground until you issue a
start mission (or takeoff) command.