Add global variable option for swf location.

The problem is, you can't set WebSocket.__swfLocation before you load
web_socket.js (because it creates the WebSocket global), but you also
can't reliably set WebSocket.__swfLocation after because if you are
doing dynamic script file includes then the onload (i.e.
WebSocket.__initialize) may fire before you have a chance to set
Websocket.__swfLocation.

include/web-socket-js/web_socket.js

@@ -293,6 +293,9 @@
   WebSocket.__tasks = [];
 
   WebSocket.__initialize = function() {
+    if (WebSocket__swfLocation) {
+        WebSocket.__swfLocation = WebSocket__swfLocation;
+    }
     if (!WebSocket.__swfLocation) {
       console.error("[WebSocket] set WebSocket.__swfLocation to location of WebSocketMain.swf");
       return;