Hydrazine Princess

• Fixed a bug where nobody could download (#185)!
• sha1 sums in the CKAN registry are working again.
• Installing, uninstalling, and upgrade operations are now transactional. If something goes wrong, your GameData directory and CKAN registry are restored to their former state. Yes, this is awesome.
• ckan list shows which modules are providing virtual packages.
• ckan install better understands virtual packages, and gives suggested choices.