Update wpt server driver, add pywebsocket.

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "tools/w3c/wptserve"]
 	path = tools/w3c/wptserve
 	url = https://github.com/w3c/wptserve.git
+[submodule "tools/w3c/pywebsocket"]
+	path = tools/w3c/pywebsocket
+	url = https://github.com/w3c/pywebsocket.git

pywebsocket @ b2e1d110

+Subproject commit b2e1d11086fdf00b33a0d30c504f227e7d4fa86b

tools/w3c/scripts/server.config.default.json

-{
-    "host": "web-platform.test",
-    "ports": {
-        "http": [ 8000, "auto" ],
-        "https": [ "auto" ]
-    },
-    "check_subdomains": true,
-    "log_level": "debug",
-    "bind_hostname": true
-}
+{"host": "web-platform.test",
+ "external_host": null,
+ "ports":{"http":[8000, "auto"],
+          "https":[],
+          "ws":["auto"]},
+ "check_subdomains": true,
+ "log_level":"debug",
+ "bind_hostname": true}