Fix to determining JSON directory location.

[ptth222]

If you run a program from the same directory that the JSON file is located in and use a relative path to create the file object, then the "name" property will only return the name of the file and you won't be able to parse the directory the file is in, which results in an error. I have changed the code to use the pathlib library to first resolve the file object name property into a full path and use the parent property to get the directory it is in.

[proccaserra]

@ptth222 thanks for the PR! while this is distinct from issue #516 it affects the same function. @terazus let's have a look at this

[terazus]

This should be mergeable once #511 is merged.