Implemented Zoom

lib/window.rb

@@ -14,6 +14,10 @@ class IMICRTS
       @last_update_time = Gosu.milliseconds
     end
 
+    def close
+      push_state(Closing) unless current_state.is_a?(Closing)
+    end
+
     def delta_time
       Gosu.milliseconds - @last_update_time
     end