DAS priority reversal (#25)

* Reversed the priority of key presses when charging DAS.
* Made it an actual config option.
* Config should be false by default.

main.lua

@@ -12,6 +12,7 @@ function love.load()
 	config["side_next"] = false
 	config["reverse_rotate"] = true
 	config["fullscreen"] = false
+	config["das_last_key"] = false
 
 	love.window.setMode(love.graphics.getWidth(), love.graphics.getHeight(), {resizable = true});