- separate out the version into a variable (again -- this was moved **into**
project() long ago, but now there's a desire to have the value before
reaching the project() command)
- rename CALAMARES_VERSION_RC to something more sensible.
- remove empty useless HACKING
- remove unused cppcheck.sh
- migrate the AppImage docs to the wiki (which doesn't moan about licensing)
- try a HTML-style comment in the RELEASE docs