v0.9.1

• Co-op added (supports up to 4 players). Defaults to singleplayer but can be changed real-time by pressing the number keys.
• Added support for xinput controllers with simplified controls where each face button corresponds to an action
• Support for high framerates via interpolated entity positions at render-time
• Fixed bug where moving from second submap to the first one broke the game
• Audio volume can be changed via INI file
• Scale of game can be changed via INI file
• Bilinear filter can be turned off via INI file (defaults to off)