Change stats data file path for better cachability.

* Put stats json files in thier own dir so we can increase cache times.
* Modify paths to files in JS and use static path from template.
* Add Unipath for cleaner and easier python path manipulation.
Switch from Unipath to pathlib.

Also clean up some pep8.
Merge pull request #80 from pmclanahan/change-map-data-path

Change stats data file path for better cachability.