Misc. design tool features

[ErikDeBruijn]

• [ ] Graphical history (entries/changes should have names and should appear in a list like in photoshop or the Upverter screenshot below)
• [ ] Collaborators should be listed in the dropdown. As a guest, viewing or editing makes you a collaborator (be inviting!)
• [ ] Switching between Blockly interface and 3D view direct editing should be easy. The should be visible directly like the split view of Dreamweaver.
• [ ] Last saved: "Autosaved 20 seconds ago." (when you make a change, autosave again and show that this has happened like the Upverter screenshot below)