AP_ServoRelayEvents: fixed disabling repeated events on set_servo()
RC_Channel: simplify the setup of aux channels

avoid the nasty mess of #if lines, as the info is in the constructor
anyway
Plane: use new RC_Channels API
Copter: use new RC_Channels API
Rover: use new RC_Channels API
RC_Channel: added flaperon1 and flaperon2 function outputs
Plane: added flaperon support

this adds FLAPERON_OUTPUT and FLAP_IN_CHANNEL to allow both manual
and auto flap control for both normal flaps and flaperons
Plane: allow FLAP_IN_CHANNEL to control k_flap and k_flap_auto too