Allow transparency on player skulls + Hang on ceilings like lanterns

Allow transparency on player heads as it would allow for massive creativity in terms of skins and building. Transparency would ONLY be supported on player heads, not on players wearing the skin, so a transparent head skin would have a transparent player head, but the player wearing it would show black. This is to prevent PVP explotation. This would allow for custom armors and hats to be created, as well as multiple possible build tools. 

In addition, allow them to hang on ceilings like lanterns. They can be placed on the floor, it makes sense they can be placed on the ceiling as well.