10.9.0: Updated mime types

Features

• Generated util.MimeType from the media type database over at
  https://github.com/jshttp/mime-db, which in turn consists of lists
  compiled from IANA registrations, Apache and Nginx. See issue #264
  (@thekid)

Bugfixes

• Fixed issue #265: Environment::variables() empty on certain environments
  by replacing $_ENV by $_SERVER, see PR #266
  (@thekid)