I removed the rename and mv functions as when I wrote the tests I realised the function implied the pathname object would be updated to reflect the moved or renamed file. However that cannot be done. Also frankly I think writing it out in full makes clearer code.
Because formula don't get named unless the brew kit instantiates them accessory formula were getting named "__UNKNOWN__". Which sucks.
This isn't ideal for me as I made the naming use @name and @version to ensure unique naming. Now it is possible to have name clashes in the cache. So I need to solve it better at some point.
