Alter channel unload behavior, add additional checks

- Should prevent "write after end" errors caused by unloading a channel before it finishes loading
- Might prevent strange cases of playlists gone wild

tests/fastQuit.js

@@ -0,0 +1,9 @@
+var io = require('socket.io-client');
+
+var socket = io.connect('http://localhost:1337');
+
+// connect, join a room, then disconnect as quickly as possible
+socket.on('connect', function () {
+    socket.emit('joinChannel', { name: 'test' });
+    socket.disconnect();
+});