Add Autobahn test suite for websockets

We're using the existing test suite for websocket servers from the
Autobahn project to verify that out websockets implementation is
sane. A CT test suite and python module wrapping the test suite has
been added. The test suite is run when the 'make inttests' target
is executed.

test/websocket_echo_handler.erl

@@ -0,0 +1,34 @@
+%% Feel free to use, reuse and abuse the code in this file.
+
+-module(websocket_echo_handler).
+-behaviour(cowboy_http_handler).
+-behaviour(cowboy_http_websocket_handler).
+-export([init/3, handle/2, terminate/2]).
+-export([websocket_init/3, websocket_handle/3,
+	websocket_info/3, websocket_terminate/3]).
+
+init(_Any, _Req, _Opts) ->
+	{upgrade, protocol, cowboy_http_websocket}.
+
+handle(_Req, _State) ->
+	exit(badarg).
+
+terminate(_Req, _State) ->
+	exit(badarg).
+
+websocket_init(_TransportName, Req, _Opts) ->
+	Req2 = cowboy_http_req:compact(Req),
+	{ok, Req2, undefined}.
+
+websocket_handle({text, Data}, Req, State) ->
+	{reply, {text, Data}, Req, State};
+websocket_handle({binary, Data}, Req, State) ->
+	{reply, {binary, Data}, Req, State};
+websocket_handle(_Frame, Req, State) ->
+	{ok, Req, State}.
+
+websocket_info(_Info, Req, State) ->
+	{ok, Req, State}.
+
+websocket_terminate(_Reason, _Req, _State) ->
+	ok.