Minor tweaks to tests.
Simplified date handling in the views.
Renamed views and simplified their URLs.
Changed how the templates handle dates in URLs.
Updated tests to reflect changes in URLs.
Removed hard limit for time period, it's up to the user to decide I think.
Renamed get_date to validate_date and only return None on failure.
Updated ENV variables.
Updated tests to use PRLEIN_PERIOD_RANGE.
Misc. tweaks.