Regrowth 0.7
No second World creation without Restart the Minecraft Client.
I have made a new world with 0.7. It was a verry bad Spawn Location. Tiny iland (5 Blocks) in the middle of a huge Ocen. I closed the world, delete the savegame, and create a new one. But i ended up in the minecraft Startmenue. After restart Minecraft, it was possible to create a new one. Next bad spawn Location. delete world, create a new, ended up in minecraft startmenue. I have try it at 0.6.5, here u can create worlds after deleting the old world.
I have also the Problem, with finishing the ''Such aTool'' quest