fix(core-xhr.html): GET params sometimes not be added to querystring

If the method is set to "get" (instead of "GET") via the options, params will not be URL encoded and included as query parameters in the URI.  Case should not be a factor when checking the method of the request.

core-xhr.html

@@ -51,7 +51,7 @@
         var async = !options.sync;
         //
         var params = this.toQueryString(options.params);
-        if (params && method == 'GET') {
+        if (params && method.toUpperCase() == 'GET') {
           url += (url.indexOf('?') > 0 ? '&' : '?') + params;
         }
         var xhrParams = this.isBodyMethod(method) ? (options.body || params) : null;