Just adding my voice to the many anxious about the fact that 0.6.0 doesn't save new or altered structures and landscapes.

*What I expected to happen ...
That Changes I had made to my world would be saved on exit.

What actually happened was...:
On quitting and returning to the same world a little while later, none of the changes I made to structures and landscapes had saved. However collected items remained in my inventory.

Steps to Reproduce:
1. Open any survival mode world
2. Destroy some blocks
3. Add some blocks
4. Exit to menu ... Quit to title
5. Restart same world
6. Last changes have disappeared
7. If this doesn't show the bug, try loading a different world and repeat steps
8. Return to the original world