Version 3.1

• all calendar data moved from a MySQL database to JSON files, that can be tracked in the repository
• the Calendar data for the Universal Calendar, as contained in the JSON files, is now translatable to other languages through a Weblate project
• the frontend and any implementations of the API have been moved to their own separate repositories,
  only the API code remains in this repository
• the PHP source code for the API has been pretty much completely rewritten, using classes and enum type classes
• all translatable strings in the PHP source code have been ported to gettext, and are now managed in a Weblate project
• parameters diocesanpreset and nationalpreset have been renamed to diocesancalendar and nationalcalendar
• API now supports POST requests that send JSON in the body instead of Form Data
• Data type can be set through the Accept header rather than the returntype parameter
• Language can be set through the Accept-Language header rather than the locale parameter
• Same as tag/release v3.0 with the addition of a single typo fix, an enum that was in camelcase instead of uppercase. This bug was preventing iCal feeds from being generated correctly.