[all] Issue 4 fixed (Mixer menu)

[sky9x / Taranis] Issue 1 fixed (PlayFile/Play were called from an interrupt). To be tested and re-tested
[all] FrSky alarms are not any more sent from the 10ms interrupt, but from the main loop. To be tested as well

src/stock/board_stock.cpp

@@ -306,7 +306,7 @@ bool getBackLightState()
   return (bl_target==g_eeGeneral.blOnBright);
 }
 
-void fadeBacklight() //called from per10ms()
+void backlightFade() //called from per10ms()
 {
   if (bl_target != bl_current) {
     if (bl_target > bl_current)