Adding support for multiple versions

[Jacob Redding]

First off, Awesome project and thank you for putting so much time into this! I've used the output on a research project to understand more about the Drupal community and a typical developer life cycle.

I forked the code and extended it to all versions of Drupal. Although the need for reports on all versions primarily suits my needs it might be useful for others as well. Before I submit a pull request (which would substantially alter multiple files) I wanted to get your take on supporting multiple versions of Drupal.

Something you'd like to support going forward?