Cap construction practice

The first two commits are the meat of the PR, they cap skill advancement for construction in the same way as we've been doing for crafting.  Thanks to Akhier the Dragon hearted for pointing out the omission.
The high points are that lvl 0 (most construction recipes) can get you to lvl 1, 1 gets you to 2, two gets you to 4, 4 gets you to 7, and 6+ gets you to 10.

The last commit is a cleanup, turns used to be a member of game, instead of including game in skills, I passed in the value.  Now that calendar::turn is a global resource, skill can access it directly, cleaning up a bunch of code.