added an update_overlay event and drawing text with Engine::drawText()

git-svn-id: svn://anubis/anaglym/trunk@163 99a6e188-d820-4881-8870-2d33a10e2619

tests/cratestack.lua

@@ -43,6 +43,6 @@ function mouse_moves(x, y, xrel, yrel)
     ag.println("mouse_moves ", x, ", ", y)
 end
 
-function update_event()
-    ag.createSolidTextBox("Hi there everyone!", 0, 0, 0)
+function update_overlay_event()
+    ag.drawText("Hi there everyone!", 1, 0.7, 0, 16, 40, 40)
 end