Fixed some issues in dragging sprites with snap-to-center and world coordinates.

Tests/input/touch priority.js

@@ -23,6 +23,6 @@
         sonic.input.enableDrag();
     }
     function render() {
-        game.input.renderDebugInfo(32, 32);
+        Phaser.DebugUtils.renderInputInfo(32, 32);
     }
 })();