I simplified this to just remove mobs on login and island teleport. The
mobs to keep are currently hard coded. They could be taken from settings
in the future.
This branch adds a world aspect to almost all commands. Although the
Bukkit World class is used for reference, the world includes any nether
or end worlds too. By enabling multiworld, things like the protection
grid will operate independently in different world groups. The idea is
to enable one plugin to run mutliple worlds. For example run AcidIsland,
ASkyGrid and BSkyBlock at the same time.
In addition to this big change, I added an admin command to copy and
paste "simple" schematics that I called "schems". It does not work
completely correctly right now, especially for chest contents.
