Implented to_str as fallback even if to_path should be available
Implented to_str as fallback even if to_path should be available

In mri if a class defines to_str the String returned from this Method is
used as Pathname. In rbx you have to define to_path to get the same
behaviour.

This would use to_str as fallback if the Class provided as Path doesn't
implement to_path.

rubysl/rubysl-pathname