Added Workshop support for custom levels.
This still needs some polish around the menus, but wanted to make sure the feature was live in time for the first sale.
If you already have local custom levels, these now need to be in sub-directories with the same name as the .zip and .cfg. Expect cleaner documentation for custom levels in the near future.
Also expect another patch very soon to add in support for preview images. I thought you'd be able to set those from the item page on the workshop, and you cannot.