to anticipate gnorm.org went down, dependencies are moved to github

What's Changed

• change how gnorm.org downloaded by @johnjerrico in #72
• bugfix wrong placement gnorm folder by @johnjerrico in #73
• bugfix gnorm download not working by @johnjerrico in #74
• Bugfix/gnorm download command by @johnjerrico in #75

Full Changelog: v0.2.19...v0.2.20