APM: added a new type of auxilary aileron, with rc input

a AileronWithInput assumes you have setup your RC transmitter to give
the right trim and input on the secondary aileron

ArduPlane/Attitude.pde

@@ -368,6 +368,11 @@ static void set_servos(void)
         int16_t aileron_in = g.channel_roll.pwm_to_angle_dz(0);
         RC_Channel_aux::set_servo_out(RC_Channel_aux::k_aileron, aileron_in);
 
+        // this aileron variant assumes you have the corresponding
+        // input channel setup in your transmitter for manual control
+        // of the 2nd aileron
+        RC_Channel_aux::copy_radio_in_out(RC_Channel_aux::k_aileron_with_input);
+
         // copy flap control from transmitter
         RC_Channel_aux::copy_radio_in_out(RC_Channel_aux::k_flap_auto);
 
@@ -379,7 +384,9 @@ static void set_servos(void)
         }
     } else {
         if (g.mix_mode == 0) {
+            // both types of secondary aileron are slaved to the roll servo out
             RC_Channel_aux::set_servo_out(RC_Channel_aux::k_aileron, g.channel_roll.servo_out);
+            RC_Channel_aux::set_servo_out(RC_Channel_aux::k_aileron_with_input, g.channel_roll.servo_out);
         }else{
             /*Elevon mode*/
             float ch1;

ArduPlane/radio.pde

@@ -169,7 +169,11 @@ static void trim_control_surfaces()
     if(g.mix_mode == 0) {
         g.channel_roll.radio_trim = g.channel_roll.radio_in;
         g.channel_pitch.radio_trim = g.channel_pitch.radio_in;
-        RC_Channel_aux::set_radio_trim(RC_Channel_aux::k_aileron);
+
+        // the secondary aileron is trimmed only if it has a
+        // corresponding transmitter input channel, which k_aileron
+        // doesn't have
+        RC_Channel_aux::set_radio_trim(RC_Channel_aux::k_aileron_with_input);
     } else{
         elevon1_trim = ch1_temp;
         elevon2_trim = ch2_temp;