play 'plop' sound on send button click

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -1426,6 +1426,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
       }
       else {
         processComposeControls(ACTION_SEND_OUT);
+        MessageNotifier.playSendSound();
       }
     }
 

src/org/thoughtcrime/securesms/notifications/MessageNotifier.java

@@ -118,7 +118,7 @@ public class MessageNotifier {
       return;
     }
 
-    if (Prefs.isInChatNotifications(instance.context)) {
+    if (Prefs.isInChatNotifications(instance.context) && instance.soundOutLoaded) {
       instance.soundPool.play(instance.soundIn, 1.0f, 1.0f, 1, 0, 1.0f);
     }
   }