Version 3.1 Support

Added support for version 3.1. Changed the ResourcePackage so that it downloads the tag version from Github instead of the branch version. We use maintenance branches now, so there is no 3.1 branch, but there are v3.1-gold and v3.1 (sdk) tags. Github also strips the "v" from the zip once you download it, so there is some code to deal with that quirk.