Changed naming of the mixers to get rid of umbiguity as outputs are actually going to be driven by io, not fmu

Implemented automatic lookup for the .aux.mix file if it exists

ROMFS/px4fmu_common/init.d/rc.interface

@@ -3,19 +3,30 @@
 # Script to configure control interface
 #
 
+set SDCARD_MIXERS_PATH /fs/microsd/etc/mixers
+    
 if [ $MIXER != none -a $MIXER != skip ]
 then
 	#
-	# Load mixer
+	# Load main mixer
 	#
+    
+    if [ $MIXER_AUX == none ]
+    then
+        MIXER_AUX = $MIXER.aux
+    fi
 	
 	# Use the mixer file from the SD-card if it exists
-	if [ -f /fs/microsd/etc/mixers/$MIXER.mix ]
+	if [ -f $SDCARD_MIXERS_PATH/$MIXER.main.mix ]
 	then
-		set MIXER_FILE /fs/microsd/etc/mixers/$MIXER.mix
-	else
-		set MIXER_FILE /etc/mixers/$MIXER.mix
-	fi
+		set MIXER_FILE $SDCARD_MIXERS_PATH/$MIXER.main.mix
+	# Try out the old convention, for backward compatibility
+	elif [ -f $SDCARD_MIXERS_PATH/$MIXER.mix ]
+    then
+        set MIXER_FILE $SDCARD_MIXERS_PATH/$MIXER.mix
+    else
+        set MIXER_FILE /etc/mixers/$MIXER.main.mix
+    fi
 	
 	if [ $OUTPUT_MODE == mkblctrl ]
 	then
@@ -80,14 +91,31 @@ then
 		pwm failsafe -d $OUTPUT_DEV $FAILSAFE
 	fi
 fi
-
+   
 # check if should load secondary mixer
-if [ $MIXER_SEC != none ]
+if [ $MIXER_AUX != none ]
 then
-	if fmu mode_pwm
-	then
-		mixer load /dev/pwm_output1 /etc/mixers/$MIXER_SEC.mix
-	else
-		tone_alarm $TUNE_ERR
-	fi
-fi
+    #
+    # Load aux mixer
+    #
+    
+    set MIXER_AUX_FILE none
+    
+    if [ -f $SDCARD_MIXERS_PATH/$MIXER_AUX.mix ]
+    then
+        set MIXER_AUX_FILE $SDCARD_MIXERS_PATH/$MIXER_AUX.mix
+    elif [ -f /etc/mixers/$MIXER_AUX.mix ]
+    then
+        set MIXER_AUX_FILE /etc/mixers/$MIXER_AUX.mix
+    fi
+    
+    if [ $MIXER_AUX_FILE != none -a $FMU_MODE == pwm ]
+    then
+    	if fmu mode_pwm
+    	then
+    		mixer load /dev/pwm_output1 $MIXER_AUX_FILE
+    	else
+    		tone_alarm $TUNE_ERR
+    	fi
+    fi
+fi