fix call to File.stat! as File.Stat is a now a struct

File.Stat was converted from a record to a struct in dc768eb in elixir
Merge pull request #35 from mathieul/patch-1

fix call to File.stat! as File.Stat is a now a struct
Remove old comprehensions syntax
Update README.md

Add a note regarding Elixir/Plug master
Improve missing cowboy message
Update to Elixir v0.13.2
Make package a map
Remove dependency on hygiene: false
Release v0.4.4
update parse_req_multipart for cowboy 0.10.0