Copter: make tradheli use angle boost for stabilize mode #759

Job	Run time
build (base)	2m 4s
build (clang)	1m 57s
autotest (sitltest-rover)	15m 43s
autotest (sitltest-sailboat)	2m 45s
autotest (sitltest-balancebot)	7m 52s
	30m 21s

Provide feedback