Improved on the state handling while showing/hiding screens

Also added simple debug logging

example/main.script

@@ -1,6 +1,7 @@
 local monarch = require "monarch.monarch"
 
 function init(self)
+	monarch.debug()
 	msg.post("@render:/", "clear_color", { color = vmath.vector4(0.4, 0.6, 0.8,1.0) })
 	msg.post("#", "init_monarch") -- wait until init() has been called for all screen.script instances
 end