Spread the distribution of construction difficulties out a bit.
Drop makeshift bed to difficulty 3.
Actually prevents flower-handling in Winter

Turned out you could pick flowers just fine in the middle of Winter--it
gave the message but fell through.

This puts paid to that!
Merge pull request #8748 from KA101/UCantPickThis

Actually prevents flower-handling in Winter
Merge pull request #8747 from jeremyosborne/difficulterer

Change some construction difficulties