The Pixhack v3 comes with an external IST8310 in the GPS.

It's used further down again.

- use the orb topic safety to check the safety state, because the actual
  safety state can come from the IO
- fix initialization if circuit breaker is set

FlightTaskAuto: move generation of the the internal waypoints to FlightTaskAuto such that they are available to all derived classes.
Change logic to update the internal triplets only when the navigator triplets have changed or when the vehicle state has changed.

-add FlightTaskAutoMapper that handles the different types of waypoint and
generates setpoints for all types except of position and loiter
- FlightTaskAutoLine generates the setpoint types position and loiter if
the flight between waypoint is a straight line

 - fixes Coverity CID 306248

 - fixes Coverity CID 306259

 - fixes Coverity CID 306260

 - fixes Coverity CID 268659

 - fixes Coverity CID 306253

- micro-CDR in PX4/Firmware (8f2facbac528cf94b6ac86828e58801c8c572994): https://github.com/eProsima/micro-CDR/commit/df48e526feca3bd140b0adf12c3c847a6d78ed79
    - micro-CDR current upstream: https://github.com/eProsima/micro-CDR/commit/92efe34b65622aef3d41315230cec0bce37a27e3
    - Changes: https://github.com/eProsima/micro-CDR/compare/df48e526feca3bd140b0adf12c3c847a6d78ed79...92efe34b65622aef3d41315230cec0bce37a27e3

* added ability to slew rate limit the roll angle output of the l1 controller
* FixedWingPositionControl: this avoids the steps in roll angle setpoint which occur when the controller
switches to a new waypoint
* GroundRoverPositionControl: adapted to new l1 API

 - the ignored warning (-Wno-missing-field-initializers) can be dropped in the future when GCC 4.8 is no longer supported

- v2.0 in PX4/Firmware (6d662c55): https://github.com/mavlink/c_library_v2/commit/fb2c4f819819e2348285bc9e03ab711ceb6c4cc1
    - v2.0 current upstream: https://github.com/mavlink/c_library_v2/commit/7014d02d665d5e8fa33f084f7c5f4dbcfd61b4b0
    - Changes: https://github.com/mavlink/c_library_v2/compare/fb2c4f819819e2348285bc9e03ab711ceb6c4cc1...7014d02d665d5e8fa33f084f7c5f4dbcfd61b4b0

Because it uses a semaphore.

Updated and added full stops to comments and did some comment/whitespace formatting in the startup scripts.

Reduces 'uorb_tests latency_test' by about 1us

The check is unnecessary. In the worst case the semaphore gets unlocked
twice, but it's not an issue because the waiter is only interested in the
first sem_post(), and the semaphore is then not used anymore.

poll() is one of the heavily used methods and thus needs to be optimized
as much as possible.

Test on Pixracer: uorb_tests latency_test
Before:
uORB note: ---------------- LATENCY TEST ------------------
INFO  [uorb_tests] mean:     40.4320 us
INFO  [uorb_tests] std dev:   1.3466 us
INFO  [uorb_tests] min:      39 us
INFO  [uorb_tests] max:      57 us
INFO  [uorb_tests] missed topic updates: 0
This Patch:
uORB note: ---------------- LATENCY TEST ------------------
INFO  [uorb_tests] mean:     31.3480 us
INFO  [uorb_tests] std dev:   1.4584 us
INFO  [uorb_tests] min:      30 us
INFO  [uorb_tests] max:      45 us
INFO  [uorb_tests] missed topic updates: 0