TECS-WIP : Consolidated patches for peer review and flight test

Conflicts:
	ArduPlane/ArduPlane.pde
	ArduPlane/Parameters.h
TECS-WIP : Fixed compile error following rebase on origin/master
Plane: fixup TECS after scheduler merge
TECS-WIP : Set speed weight to maximum during takeoff/climbout.

This allows TECS to raise the nose above the minimum set by the mission plan to regulate speed during climbout.
TECS-WIP : Modified underspeed condition for improved glide and climb rates.
TECS-WIP : Added protection for a bad descent caused by excessive airspeed demand and TECS_SPD_MAX
TECS-WIP : Added bad descent state to list of states reset on entry
TECS-WIP : Added additional states to be reset on entry
Plane : Improved launch acceleration detection using TECS 50Hz output data
Plane : Fixed compile errors
Plane : Modified takeoff detect logic to suit pusher props for hand launch
Plane : Added time delay to launch detect logic
TECS-WIP : Changes to airspeed demand rate limiter state initialisation and limiting.

These changes prevent a bad airspeed value on startup from causing an uncontrolled descent after climbout.
Plane : Modified auto takeoff throttle enable logic
Plane : Corrected bug in takeoff detection
Plane : Cleaned up takeoff detect logic updates and added a user parameter for time delay
TECS-WIP : Removed voltage reference pin defines used for PX4 analogue airspeed drift testing
TECS-WIP : Added framework for precision height mode and removed voltage reference pin defines
Revert "TECS-WIP : Removed voltage reference pin defines used for PX4 analogue airspeed drift testing"

This reverts commit e7b89d33331de747fe7405d851b8623d3eec274d.
TECS-WIP : Removed voltage reference pin code used for airspeed drift testing on PX4