Skip enqueueing to outgoing bridges on incoming remote messages. Twitter, Facebook, RSSCloud, and OStatus checks were enqueued on these when they'd never do anything but churn the queue servers.

Notice::isLocal() can replace a number of manual checks for $notice->is_local being LOCAL_PUBLIC or LOCAL_NONPUBLIC.

plugins/TwitterBridge/TwitterBridgePlugin.php

@@ -221,7 +221,7 @@ class TwitterBridgePlugin extends Plugin
      */
     function onStartEnqueueNotice($notice, &$transports)
     {
-        if (self::hasKeys()) {
+        if (self::hasKeys() && $notice->isLocal()) {
             // Avoid a possible loop
             if ($notice->source != 'twitter') {
                 array_push($transports, 'twitter');