audio/csound6: Take maintainership; Change to github
This port is broken. It both failed to fetch and failed to build afterwards.
I fixed the fetching problem: it moved to github.
So far I couldn't fix the build problem - it seems to fail due to some incompatibilities
with dependencies, but it is also badly outdated. New version doesn't build either.
The upstream needs to fix at least these two problems:
I'll come back to it after they fix these build issues.