added ag::object::setTransparency() and Engine::Object::setTransparency()

git-svn-id: svn://anubis/anaglym/trunk@316 99a6e188-d820-4881-8870-2d33a10e2619

tests/checkerpick.lua

@@ -3,9 +3,10 @@ function init_event()
     ground = ag.createBox(8, 8, 0.1, {static = true})
     ground:setTexture(checker_texture)
     ag.setCamera(10, -10, 10, 0, 0, 0)
-    hilite = ag.createBox(2, 2, 0.1, {static = true})
+    hilite = ag.createBox(2, 2, 0.1, {static = true, enable_blending = true})
     hilite:setColor(0.3, 0.5, 1)
     hilite:setPosition(1, 1, 0.1)
+    hilite:setTransparency(0.4)
 
     ag.setCursorVisible(true)
 end