Upgrade 1.2.1 "Keyboard"

This is a small update covering some changes that were requested or reported, please join our Discord community to leave your requests or bug reports. - Added a new FPS control option in the options menu. (This should fix performance issues with high refresh rate monitors) - Possible fix for Steam overlay. Following this line, a fix was also added for the Steam achievement that should work with any type of game mode. - UI fixes to improve understanding. - Upon request, the possibility of up to 4 players with a single keyboard was added. When selecting players, by pressing C on the keyboard you will be able to see the different controls. (this solution should be temporary, a key rewrite option will be added in the future).