EnumerateFiles could return path relative to mount path, not enumeration path.

[duarm]

When physfs returns the path list with enumerateFiles, it returns the path relative to the path given to it. I think it would be better if it returned the path relative to the mount point it was found, so we could more easily load the enumerated files. This would also avoid allocating the path ourselves, since we could use physfs own allocated paths directly.

Not sure if how worth would this change be at this point.