[feature] 'future/path' module: expose $HOME, $CWD etc to API

[kixxauth]

It would be great to get easy access to certain cross platform OS filesystem locations like $HOME from the 'future/path' API.

Here is the Mozilla docs explaining how to go about doing this:

https://developer.mozilla.org/en/Code_snippets/File_I%2f%2fO#Getting_special_files