One of these things is like the others

Two small changes:

1) When one market exhausts, finish the turn (this is already in the posted rules, I just forgot to mention it)

2) During the Explore Routes phase a player may discard 3 prestige in order to explore one more route than they have explorers. This change allows prestige to be fungible like other currencies

Both are fairly minor. The second should allow for more subtly interesting and challenging end-games.