0.7.0

Breaking

• The Git cache and the GitHub strategy have been dropped.
  Fabio Pelosin

Enhancements

• Improved performance of Git downloads using shallow clone.
  Marin Usalj
  Fabio Pelosin
• Added method to check if the head strategy is supported by a concreted
  downloader class.
  Fabio Pelosin
  #12

Bug Fixes

• Fixed the check for git references on Ruby 1.8.7.
  Fabio Pelosin
  #28