Convert Notch maps to MCServer

[xoft]

For Notchian servers you have your world files (.mca) in <worldname>/region/*.mca for the overworld and <worldname>/DIM<N>/region/*.mca for the nether / End. MCServer supports only one "dimension" in one world, so it expects the .mca files in <worldname>/*.mca.

For example, to use the SkyBlock map on a server, copy all *.mca files to SkyBlock/*.mca and set your settings.ini's [world]::DefaultWorld=SkyBlock

MCServer will read *.mca files, but any changes to the world will be saved into *.pak files (since MCA writing support is not yet written)