Make cowboy_req:req() opaque

Remove http.hrl in the process.

If you feel furious about this change after reaching this commit,
don't worry! You probably just need a few access or modification
functions to be added in cowboy_req for your needs. Problem is,
I don't know these. I'll be very thankful if you can open a ticket
and tell me all about it so the best solution can be swiftly
implemented to make you happy again.

src/cowboy_req.erl

@@ -118,10 +118,50 @@
 -export([to_list/1]).
 -export([transport/1]).
 
--include("http.hrl").
 -include_lib("eunit/include/eunit.hrl").
 
--type req() :: #http_req{}.
+-record(http_req, {
+	%% Transport.
+	socket = undefined :: undefined | inet:socket(),
+	transport = undefined :: undefined | module(),
+	connection = keepalive :: keepalive | close,
+
+	%% Request.
+	pid = undefined :: pid(),
+	method = 'GET' :: cowboy_http:method(),
+	version = {1, 1} :: cowboy_http:version(),
+	peer = undefined :: undefined | {inet:ip_address(), inet:port_number()},
+	host = undefined :: undefined | binary(),
+	host_info = undefined :: undefined | cowboy_dispatcher:tokens(),
+	port = undefined :: undefined | inet:port_number(),
+	path = undefined :: binary(),
+	path_info = undefined :: undefined | cowboy_dispatcher:tokens(),
+	qs_vals = undefined :: undefined | list({binary(), binary() | true}),
+	raw_qs = undefined :: binary(),
+	bindings = undefined :: undefined | cowboy_dispatcher:bindings(),
+	headers = [] :: cowboy_http:headers(),
+	p_headers = [] :: [any()], %% @todo Improve those specs.
+	cookies = undefined :: undefined | [{binary(), binary()}],
+	meta = [] :: [{atom(), any()}],
+
+	%% Request body.
+	body_state = waiting :: waiting | done | {stream, fun(), any(), fun()},
+	multipart = undefined :: undefined | {non_neg_integer(), fun()},
+	buffer = <<>> :: binary(),
+
+	%% Response.
+	resp_state = waiting :: locked | waiting | chunks | done,
+	resp_headers = [] :: cowboy_http:headers(),
+	resp_body = <<>> :: iodata()
+		| {non_neg_integer(), fun(() -> {sent, non_neg_integer()})},
+
+	%% Functions.
+	onresponse = undefined :: undefined | fun((cowboy_http:status(),
+		cowboy_http:headers(), Req) -> Req),
+	urldecode :: {fun((binary(), T) -> binary()), T}
+}).
+
+-opaque req() :: #http_req{}.
 -export_type([req/0]).
 
 %% Request API.