Toggle disableScreenSaver based on audio state

Fixes #1230

components/mediaPlayers/AudioPlayer.brs

@@ -1,6 +1,5 @@
 sub init()
     m.playReported = false
-    m.top.disableScreenSaver = true
     m.top.observeField("state", "audioStateChanged")
 end sub
 
@@ -10,6 +9,8 @@ sub audioStateChanged()
 
     reportedPlaybackState = "update"
 
+    m.top.disableScreenSaver = (currentState = "playing")
+
     if currentState = "playing" and not m.playReported
         reportedPlaybackState = "start"
         m.playReported = true