So it is the case to wait for the official spigot 1.8. So wait till law suit thingy is sorted out. I mention it because, spigot separates the world, nether, world end folders. If I combine the files into world folder then I lose all inventory and ender chest inventory. I have tried to restore the folder folder and player data but it didn't work. If spigot manage to win and update spigot then I will get me world back as it was!
The region files are the same, just in different places. Move world_nether into world/DIM1 and world_the_end into world/DIM-1 to go back to the Vanilla format. I'm not sure about the player data - I think that might have been renamed to playerdata in later versions.
