New spectators' tool: teleportation to death point

All in the title!

If this feature is disabled (in the config) or if there isn't any saved death point for the spectator, the GIO is just like before. Else, a new item is added.

![2014-09-17_13 37 57](https://cloud.githubusercontent.com/assets/1417570/4304095/b7f936e0-3e6d-11e4-8e77-886cf442e297.png)

The death cause can be hidden (displayed by default).

I use the nether star because this item is like a “target”, with the cross. (And, why not?)