Double, quadruple, multiply number of AppImage testers...

I think the number of testers of AppImages could be easily doubled, quadrupled, multiplied by two simple and one (maybe) more difficult measures:

1. Write a short tutorial with exact instructions about how to test an .AppImage:
- What are the most common mistakes an AppImage packager may make?
- How do you find these mistakes fast?
- How do you fix them?
- Which tools are available?
- Which type of problems should be reported to whom:
i. The AppImage packager
i. The AppImageKit developers

1. Put up a public call for tester volunteers, and repeat it from time to time (IRC, Twitter, articles, comments). Call should go to AppImage packagers as well!

1. (The more difficult one:) Provide an easy to use "Multi-Live-ISO-Boot" instruction set, alongside a working multi ISO boot barbones image (which users can then fill up with their own Live ISOs).