zero-length header names MUST issue a stream error
Fix cowboy:start_http/https/spdy typespecs
Fix a couple control_frame clauses that were too large
Use read_file_info/2 with {time, universal} option
Merge branch 'spdy-zero-length-header-names' of git://github.com/bgentry/cowboy
Merge branch 'types' of git://github.com/lavrin/cowboy
Don't overwrite stacktrace in `cowboy_rest:error_terminate/2`

This stacktrace is very useful in the `onresponse` hook. For example:

```erlang
internal_error_hook(500, Headers, <<>>, Req) ->
    StackTrace = erlang:get_stacktrace(),
    Headers0 = [{N, V} || {N, V} <- Headers, N =/= <<"content-length">>],
    Body = io_lib:format("~p", [StackTrace]),
    {ok, Req0} = cowboy_req:reply(500, Headers0, Body, Req),
    Req0;
internal_error_hook(Status, Headers, Body, Req) ->
    {ok, Req0} = cowboy_req:reply(Status, Headers, Body, Req),
    Req0.
```
Merge branch 'read_with_utc' of git://github.com/narma/cowboy
Merge branch 'dont_overwrite_stacktrace' of git://github.com/urbanserj/cowboy
Avoid crashing in cowboy_req on invalid Accept-Encoding header

Certain clients send malformed Accept-Encoding headers, which causes
cowboy_req to crash is compression is enabled.
Merge branch 'fix/crash-on-invalid-accept-encoding' of git://github.com/soundrop/cowboy
Update erlang.mk
Add support for the webkit deflate frame extension