Fix for respawning + /respawn command

- Player is automatically respawned when logging in
- Added /respawn command (MC 1.7 does not fail to respawn)
- Cleaned MCC command handling code, /exec is now /script

MinecraftClient/MinecraftCom.cs

@@ -549,6 +549,9 @@ namespace MinecraftClient
             if (message == null)
                 message = "";
 
+            message.Replace("\"", "\\\"");
+            message = "\"" + message + "\"";
+
             try
             {
                 byte[] packet_id = getVarInt(0x40);