git history statistics generator

The official project seems to have died and I wanted some polish done, so I've forked and added some minor changes. Enjoy!

• Generate SVG images
• Use commit date, not author date
• added max_authors_top config item, now many users to show in the authors top list, default 100
• link to this page in the "generator" output
• minor English polish
• update the default CSS to use graphs at 70% width