Added a new level, two new actors, and restructured actor scale.

New enemy, Pain Mine.  Don't hit it, it will also hurt you when it hits
you.
New enemy, Bomb.  Explodes when it dies.  Doesn't hurt you, sets off an
explosion that damages other enemies.
New Level of just mines and bombs.
Scale on the model now scales up the transforms initial scales.  This
allows the artist to set the right proportions for the actor, and scale
now simply multiplies those values.
Scale is now controlled by individual scripts instead of the actor
controller.