Fixes 1 bug (uses full monster selection) and improves mooks pricing

 * 13th age specifies that mooks are priced more expensively for level
   one and two characters. scaleFactor (previously sizeFactor) now
   takes that into account. Code is also cleaner
 * previously the recursive rules backtracked before adding the
   current allocation to the allocations list if there were no more
   monsters.