Fixed crashing with new version of Ren'Py

Thanks to @Brahex and @jorams for this fix to stop variables from being accessed before they are initialized.

New GUI-compatible DSE

This version of the DSE is compatible with the new GUI system. All DSE files were renamed to make it more obvious which ones you need and which ones you don't.

Dating Sim Engine for Ren'Py v3.12

Added a feature to have hidden statistics (courtesy of Pneumonica). Added a test for this feature. Better documentation for statistics feature.

Dating Sim Engine for Ren'Py v3.11

• Fixed a bug where skipping to the next period would not work properly, and added a test for that case.

Dating Sim Engine for Ren'Py v3.1

• More consistent styles
• Fixed a bug where it would crash if you asked it not to display the stats label or value
• More comments directing users to the parts they probably wish to change

Dating Sim Engine 3.0

This update uses screen language to improve readability and user customizability.