Updated rc.vtol_defaults to correct PWM_AUX behavior for VTOL airframes. Added PWM_AUX_RATE to rc.vtol_default and set parameters directly instead of environment variables.

hash check and heartbeat forwarding

- hash check disabling: for systems where a companion link forwards messages
to QGC (e.g. via LTE) parameter streaming will be stopped as soon as QGC
sends the request to stop the stream. If the companion side for some reason
still requires the stream to be active we need to disable QGC from stopping
the stream. Normally dronekit should be responsible for filtering out the
request from QGC but apparently this is not possible.

- disable heartbeat forwarding: dronekit does seem to get confused if
heartbeats from another system other than the autopilot get forwarded to it.
Example: Sending messages from QGC via the autopilot to dronekit running on
companion computer.

Signed-off-by: Roman <bapstroman@gmail.com>

The previous removal of the mag was not complete. It just disabled publishing. This commit conditionally removes all the the mag functionality.

looking at height rates

Signed-off-by: Roman <bapstroman@gmail.com>

    - devices in PX4/Firmware (8158cdfc): https://github.com/PX4/GpsDrivers/commit/aef48b04ff9b95350c4e5e507eea72a9e971d6a4
    - devices current upstream: https://github.com/PX4/GpsDrivers/commit/657514b26a0bf1b1ea2bf723b18449b04248822c
    - Changes: https://github.com/PX4/GpsDrivers/compare/aef48b04ff9b95350c4e5e507eea72a9e971d6a4...657514b26a0bf1b1ea2bf723b18449b04248822c

    657514b 2018-08-02 Alexis Paques - Adding UBX_MSG_RTCM3_* for additional messages
f9cf788 2018-08-02 Alexis Paques - Adding RTCM3 class documentation reference
6009a29 2018-08-02 Alexis Paques - Adding RTCM3 available output message IDs

- yaw_valid flag was always left at false which made the position controller reject the yaw setpoint of the reposition command

This checks if we are on macOS and if we have Java 8 installed. If yes,
it falls back to Java 8 by setting JAVA_HOME.

This avoids https://github.com/PX4/jMAVSim/issues/81

This should resolve the issues with Java 9/10.

These leaks are not critical but the address-sanitizer complains.
And it's better programming practice anyway.

Signed-off-by: Lukas Woodtli <woodtli.lukas@gmail.com>