Include the pathname library from stdlib ruby
Expect a Pathname instance here
Adapted test: Expect Pathname instance
Added super constructor for path

Use the super() call to pass the path to the superclass, which checks it
to be a Pathname instance
Added some Pathname argument checks
Updated path creations, we dont need to add a slash ("/") manually anymore
Add #match for Pathname class
Added require calls for new override
Fixed wrong naming of test method
Fixed wrong method call in test
Pass a Pathname here
Fix: We must generate the file name first and then join with the dirpath
Merge pull request #71 from matthiasbeyer/use-pathname

Transform code to use 'pathname', which is in stdlib since Ruby 1.9.3