[mcu_periph] gpio helper functions

also removed the old gpio1 that was used on lpc and fixedwing firmware
GLS (new)

implemented a new intercept that takes into account wind on final and APP_Angle
fixed desired altitude to match the actual setpoint
should work now with any type of vertical control since all control parameters have been removed

closes #453
[telemetry] adapt rotorcraft to new telemetry system