needed for new nuttx structure

Nose was only pointing home if your initial altitude was above the
RTL_ALT

this will remove lots of warnings when building with arduino

bug-fix to resolve 1/10th second twitch when loiter or waypoint
controller are first engaged

Bug fix to allow cli's compass motor compensation to be run from the
mission planner's terminal window

thanks to the suggestion from Kevin

the calculate_heading() based on roll/pitch is not needed anywhere

Thanks to piersh for this improvement. See

https://github.com/diydrones/ardupilot/commit/b5f0635455957d6df65c7653e3077a6fa0737ea4#commitcomment-3171806

Waypoint is considered "reached" when the intermediate point reaches the
destination

Also includes bug fix to ramp up of speed of intermediate point

Wait for 0.1s after erase and before we start writing parameters to
the log

Pair-Programmed-With: Randy Mackay <rmackay9@yahoo.com>