AC_AttControl: add rateef_rpy

rateef_rpy takes earth frame rates and applies them to the earth frame
angle targets and then converts them to body frame rates
Copter: drift moved to control_drift
Copter: sport moved to control_sport.pde
Copter: althold moved to control_althold.pde
Copter: removed althold, drift, sport from control_stabilize