Medium difficulty removed and began Treadmill algorithm.
Algorithm for Wildcards and Freebie sections added.

Some prefabs fixes made as part of this change.
Added more easy Section prefabs to support new algorithm.
Adding some stats for us to use to see which Sections are called most.
Added challenge sections with similar algorithm to freebies.
Sync scenes with treadmill algorithm by adding prefab.
Changed build settings to be visible in < 960 height screen. (800)
Fix bug where challenge and freebie didn't reset.