Oh to follow up, TileEntities do work now:
Ignore the graphical glitch in the middle image now. After I refactor it a bit to work with multiple worlds, I can integrate it into the GUI and have it working there (though you can't edit blocks there yet, and you need to have a block update to get it started, but it should be soon enough).
EDIT: Alright the refactoring is done. Which means all I will be doing until release is merging the GUI with the Simulator and providing some basic editing functionality (because nothing will happen otherwise).
Ignore the graphical glitch in the middle image now. After I refactor it a bit to work with multiple worlds, I can integrate it into the GUI and have it working there (though you can't edit blocks there yet, and you need to have a block update to get it started, but it should be soon enough).
EDIT: Alright the refactoring is done. Which means all I will be doing until release is merging the GUI with the Simulator and providing some basic editing functionality (because nothing will happen otherwise).