Added main menu, pause menu and particles

I just did a small update. Added a main menu so you don't just start into the game. Added a pause menu so you can pause and stuff. Added gpu particles for when the Sohl goes into the well. Although, even when I enlarge the bounds, it immediately goes away at a certain distance. It is something I'll look into later. It also says "fin" when all the Sohls have been collected to the well. This will most likely be the last thing I'll put into this game because this was just for the game jam or if 1 person that isn't me plays it.