Add rfc7230 test suite and update others to recent Gun

This is a large commit.

The rfc7230 test suite adds many tests from the RFC7230 document.

Gun has been updated quite a bit recently, which broke the Cowboy
suites. This is now fixed with this commit.

A new hook onfirstrequest has been added. It was very useful during
debugging of the test suites.

The initial process code has changed a little; more changes are
expected with the switch to maps for options.

test/ws_SUITE.erl

@@ -15,7 +15,7 @@
 -module(ws_SUITE).
 -compile(export_all).
 
--import(cowboy_test, [config/2]).
+-import(ct_helper, [config/2]).
 
 %% ct.
 
@@ -23,12 +23,9 @@ all() ->
 	[{group, autobahn}, {group, ws}].
 
 groups() ->
-	BaseTests = cowboy_test:all(?MODULE) -- [autobahn_fuzzingclient],
+	BaseTests = ct_helper:all(?MODULE) -- [autobahn_fuzzingclient],
 	[{autobahn, [], [autobahn_fuzzingclient]}, {ws, [parallel], BaseTests}].
 
-init_per_suite(Config) ->
-	Config.
-
 init_per_group(Name = autobahn, Config) ->
 	%% Some systems have it named pip2.
 	Out = os:cmd("pip show autobahntestsuite ; pip2 show autobahntestsuite"),