MW 1.22 and SMW 1.9beta install/upgrade

Looks good to me. I will give it a shot. Just to emphasize: One really needs to use MW 1.22+ since using Composer is frankly imho not an option for earlier versions of MediaWiki. The Extension Installer extension sadly moves all the code into a subdirectory "extensions" of its own directory which will definitively create even more confusion on top of this already very big habitual change. I works but the next upgrade always dreads. :|

[[kgh]] (talk)

I completely messed up things with MW 1.21.x and the "ExtensionInstaller" extension. Apparently or luckily this approach works as expected, too. This should also work for MW 1.19.x and 1.20.x

[[kgh]] (talk)

I need to remember documenting this too

[[kgh]] (talk)