Fix JSON files not working properly with targeted version folders

Add support for versioned JSON files

Fix an issue with "world_state" and v1.9.15

Update to Rain World v1.9.15

Add files in preparation for Rain World 1.9.14

Update SlugBase.dll to include fixes in the previous release

Fix "world_state" feature in expedition mode
Fix some bugs related to placed object filters
Fix custom sleep scenes not appearing when a dream is queued

Add support for custom slideshows
Allow colors added with "custom_colors" to be configured in co-op
Add "use_default_dreams" feature
Add "intro_scene" and "outro_scene" features
Add API for custom dreams
Fix death persistent save data not saving
Fix custom cycle lengths always using the minimum value

Fix some errors caused by the "world_state" feature
Add an API for saving persistent data

Overhaul "world_state" feature to selectively inherit and override items
Add "story_regions" feature
Fix "start_room" applying in safari mode