Merge branch 'accept-custom-config' of github.com:mojombo/jekyll into…

… accept-custom-config

* 'accept-custom-config' of github.com:mojombo/jekyll:
  Added the missing '>'
  Using default config if config passed is either empty or null
  Tests for --config
  Fixed merge conflict
  Added the missing '>'
  Using default config if config passed is either empty or null
  Tests for --config
  Raise error if no config file is passed to --config
  Moved --config block to below importer switches
  added custom config file