Merge remote-tracking branch 'upstream/master'

* upstream/master: (41 commits)
  Audit external files
  When deleting an object, remove it's files too
  Fixed facet links
  Skip the threshold check for thumbnails and proxies
  Upgrade sufia
  Support MXF as a video type
  Fix ftp logging
  Logging for change_dir
  user is instance variable
  more logger for get
  logger for get
  More config for ftp
  Allow a -E option for environment
  Remove the failing test
  Fixed download controller stub
  forgot to add files
  Basics of an FTP server
  Update readme with instructions for ftp server
  Basics of the ftp server
  Allow filtering by guest
  ...

Conflicts:
	Gemfile
	Gemfile.lock
	app/models/generic_file.rb