- __BEGIN_DECLS is for declarations not definitions
- getprogname() declaration is in err.h

Useful to test maximum sequential write speed to the SD Card

It seems that the stack size was exhausted on Snapdragon.

removes use of vehicle arm status message

Remove unused gyro scale factor parameter
Change gyro and accelerometer bias noise parameters to more intuitive units
Updated tuning defaults

Numerous EKF updates for improved accuracy and stability

The hexagon-clang is clang-3.5 and does not support -fcheck-new.

- tested in acro mode with good orientation lock and good response
- tested in stabilize mode with good attitude tracking
- needs more testing and maybe small adjustments

GCC assumes that operator new never returns null, but throws an exception
instead. This is defined by the C++ standard, and thus ok. But we disable
exceptions with -fno-exceptions, so we break this assumption. GCC then goes
ahead and removes some of our nullptr checks. This flag removes the
assumption.

This adds ~1.4kB to the binary size of the px4fmu-v4 target.

Navigator: differentiate between takeoff and reposition commands, perform calculations for repositions only when armed.