Add tones, including a launch countdown sequence.

prog/launchpad.ks

@@ -11,6 +11,7 @@
 
 RunOncePath("/lib/systems").
 RunOncePath("/lib/ui").
+RunOncePath("/lib/sound").
 
 ClearGuis().
 
@@ -38,6 +39,9 @@ function preLaunch {
   // turn on generator and fuel flow
   enableLaunchpadFlow().
 
+  InfoTone().
+  wait 2.
+  
   local duration is options["Spool-up Time"]:TEXT:ToNumber().
   lock THROTTLE to 0.
   stage.