Group.sendToBottom(child) is the handy opposite of Group.bringToTop()
Group.moveUp(child) will move a child up the display list, swapping with the child above it.
Group.moveDown(child) will move a child down the display list, swapping with the child below it.
InputHandler.pixelPerfectOver - performs a pixel perfect check to see if any pointer is over the current object (warning: very expensive!)
InputHandler.pixelPerfectClick - performs a pixel perfect check but only when the pointer touches/clicks on the current object.