Bug / Performance fixes - Multi-threaded saves

Some players were reporting performance and save/load issues. I thiiiiink I've fixed those by creating a multi-threaded save system. I've tested it myself, but these issues are often machine dependent and rare, so it's possible I haven't caught an issue. Please let me know if you experience save/load issues after you download this patch!

For more details about it, and to send bug reports, here is a discussion thread on the topic https://steamcommunity.com/app/2820000/discussions/0/4360123163646714934/