Merge remote-tracking branch 'upstream/master'

* upstream/master: (35 commits)
  make README reflect latest changes
  URL Tools Plugin
  added a comment to the composer installation alias
  added Composer completition and aliases
  added two aliases to Symfony2 Plugin
  fix test aliases
  Missing comment line
  look for test/unit instead of test/units. #typo
  Correct error message.
  Clean up doc
  Jira ticket shortcut to browse existing issues or create a new issue.
  Add zeus plugin
  Make rvm prompt function a bit cleaner
  Fixing the rvm_prompt_info command, now it will not show empty parens if no rvm is currently being used
  Add link to gist
  Updated documentation for agnoster theme
  Use HISTFILE evironment variable directly rather than copying it
  added autojump plugin support for mac os x + port
  Colemak plugin
  Per directory history plugin
  ...