Making source tarballs

[Boudewijn Rempt]

I've added Krita to the generic KDE script for making source tarballs:

https://community.kde.org/MakingTarballs

This makes it pretty easy to make source tarballs for our releases. Of
course, we also should use those source tarballs instead of a direct
git checkout to make our releases, but currently my build systems aren't
setup for that.

-- 
Boudewijn Rempt | http://www.krita.org, http://www.valdyas.org