Changes default behaviour for CLASS 0 messages

"Flash" messages are no longer handled by TS.

Sorry for the multiple pulls -- previous request had a cut+paste typo.

src/org/thoughtcrime/securesms/service/SmsListener.java

@@ -31,10 +31,16 @@ public class SmsListener extends BroadcastReceiver {
   private static final String SMS_RECEIVED_ACTION = "android.provider.Telephony.SMS_RECEIVED";
 
   private boolean isExemption(SmsMessage message, String messageBody) {
+
+    // ignore CLASS0 ("flash") messages
+    if (message.getMessageClass() == SmsMessage.MessageClass.CLASS_0)
+      return true;
+
     // ignore OTP messages from Sparebank1 (Norwegian bank)
     if (messageBody.startsWith("Sparebank1://otp?")) {
-      return (true);
+      return true;
     }
+    
     // Sprint Visual Voicemail
     return 
       message.getOriginatingAddress().length() < 7 &&