Added Controller Support — Touhou Library Survivors Steam update #410157

Hello there. Previously you could use a controller during gameplay (dual stick with any trigger or shoulder to fire). However, a controller did not work in the interface, which is maybe not ideal when an upgrade screen pops up about 54 times a game. Now you can use the controller as a virtual mouse on these screens. I did experiment with a more natural control mechanism, but I personally found it did not retrofit well. I switched out the entire input system for this to work, including for keyboard and mouse, so let me know if you see any major problems. But it seems okay with my testing.