v1.8.1: More runtime options for troubleshooting

I added an argument "simpletextures" that will disable automatic texture generation upon startup. This will make the game start up much faster. I did this to try and troubleshoot an issue here: https://steamcommunity.com/app/2186670/discussions/0/3764479392873774240/ I don't think this issue is widespread, so all of you should still be able to use the "normal" options without a problem. - Phr00t