Alpha 8.7.1 out on testing branch

EDIT: Alpha 8.7.2 vastly improves thumbnails for blueprints.
EDIT: Alpha 8.7.3 fixed bugs in miniature generator and added delete button to blueprint window

I've added a building blueprint system, which allows you to select a building and save to a file, which you can then build again, exactly like cloning rooms. You can also upload your blueprints to the Steam Workshop.

I'll be releasing this publicly tomorrow if nothing goes wrong.

Also fixed some bugs.