Implement random attack pattern for Scott

Attack selection is based on a weighted pool of moves.  Some moves are
weighted more heavily than others, and will therefore be used more
often.
Implement field conditions for Rank 4 magic

Inferno and Subzero cause residual fire and ice damage respectively,
General Disarray randomizes ranks of actions (up to 15 times), and
Thunderstorm inflicts Zombie at the end of a battler's turn 10% of the
time.