0.2

CHANGES:

• Narrowed the type of Util.fd_of_unix (@reynir)
• Use older school uerror instead of caml_uerror (@reynir)
• Added c_standard to dune build flags (@reynir)
• Addded ppoll(2) discoverability and a mini compat layer (@haesbaert)
• Improved tests (@haesbaert)
• Re-added macos support (@haesbaert)