Refactor MMS send/download to be synchronous.

1) Make the radio change a synchronous action with a timeout.

2) Move the send logic into an MmsTransport, in preparation for
   UniversalTransport composition.

3) Move the download logic into a synchronous receiver.

src/org/thoughtcrime/securesms/database/MmsDatabase.java

@@ -240,6 +240,11 @@ public class MmsDatabase extends Database implements MmsSmsColumns {
     notifyConversationListeners(getThreadIdForMessage(messageId));
   }
 
+  public void markAsSending(long messageId) {
+    updateMailboxBitmask(messageId, Types.BASE_TYPE_MASK, Types.BASE_SENDING_TYPE);
+    notifyConversationListeners(getThreadIdForMessage(messageId));
+  }
+
   public void markAsSent(long messageId, byte[] mmsId, long status) {
     SQLiteDatabase database     = databaseHelper.getWritableDatabase();
     ContentValues contentValues = new ContentValues();

src/org/thoughtcrime/securesms/database/ThreadDatabase.java

@@ -349,7 +349,7 @@ public class ThreadDatabase extends Database {
     }
   }
 
-  public Recipients getRecipientsForThreadId(Context context, long threadId) {
+  public Recipients getRecipientsForThreadId(long threadId) {
     SQLiteDatabase db = databaseHelper.getReadableDatabase();
     Cursor cursor     = null;