SotBE S7: map changes to make scenario slightly less tedious

Add some road hexes and a couple villages.
SotBE S7: minor change to a message
SotBE S7: change locations and number of scorpions

They are slightly farther away at the beginning now.  Also, there's a
new event that adds new scorpions for the first 10 turns.
SotBE S7: balancing adjustments to gold, turns, AI parameters