Add checks for dead channels

lib/channel/channel.js

@@ -360,6 +360,11 @@ Channel.prototype.acceptUser = function (user) {
 };
 
 Channel.prototype.partUser = function (user) {
+    if (!this.logger) {
+        Logger.errlog.log("partUser called on dead channel");
+        return;
+    }
+
     this.logger.log("[login] " + user.longip + " (" + user.getName() + ") " +
                     "disconnected.");
     user.channel = null;

lib/channel/chat.js

@@ -108,7 +108,7 @@ ChatModule.prototype.shadowMutedUsers = function () {
 ChatModule.prototype.handleChatMsg = function (user, data) {
     var self = this;
 
-    if (!this.channel.modules.permissions.canChat(user)) {
+    if (!this.channel || !this.channel.modules.permissions.canChat(user)) {
         return;
     }
 
@@ -135,6 +135,10 @@ ChatModule.prototype.handleChatMsg = function (user, data) {
 };
 
 ChatModule.prototype.handlePm = function (user, data) {
+    if (!this.channel) {
+        return;
+    }
+
     var reallyTo = data.to;
     data.to = data.to.toLowerCase();