October maintenance update

Hello again! It's the usual maintenance update. (Re-released just now to remove something unfinished that sneaked in.)

Changes from the last update are below. As always, the complete changelog is on the forums.

• The artbook can now be opened in-game via the gallery.

• The engine doesn't recompile itself on first run for fun anymore. This was why 100 files were always redownloaded when verifying integrity.

• Fixed the skip after choice preferences being reversed.

• Fixed a few misnamed tracks in the music room.

• Achievement progress isn't cached in save data anymore.