Update to: Multi World Inventories

So, I'm pretty sceptical of this - Will need to test immensely.

What this should do is split the world name down into one of three things:

worldname
worldname the end
worldname nether

No matter which one it is, the world name is the first element. So I split it up into the possible pieces, and get the first element and use that as the inventory name. If the world name is 'world' then I load survival as thats what we've been using since I coded the inventory handler.

No inventories should be lost except for those of nether/end inventories in the alternate worlds (not the main world)