I made it generic in case there would be other sources not supporting "Copy" or other places where it would be needed
doxy the new functions please (yes, i know there are bad examples to follow ;))
not immediately obvious what output and input means in the context.
Would SupportsRead.. and SupportsWrite... be better?
yeah, that's better.
FIX: Don't show the "Copy" option in the file manager for sources not…
… supporting it (i.e. videodb)