I've fixed some issues with the editor, so it's pretty usable now if you know what you're doing.  Not everything is implemented yet, but it's enough to actually build some maps with, so if someone wants to work on maps for the demo, I'd be happy to show you around the editor.  I've updated the git repository and the windows build with the new changes.

Note: The editor in the windows build was accidentally built in release mode and doesn't come with the necessary DLL files.   I'll recompile it later tonight and fix this issue.