balanced stats, monsters still broken.

Modified Stat effects and how they apply (Str, Agi, Def).
- Current logic is only implemented in Strong Attack (will need to
modify all other abilities)
- Moved ApplyDefense() to StatAlgorithms class
- Modified monster power gains per level increase
- Modified the Strength calculation method in StatAlgorithms to
GetPercentStrength(Hero hero, int percent).

NOTE:* In order to balance monsters better, if possible, we should apply
a flat percent damage reduction to abilities used by monsters based on
their AI. WeakAI = 75% damage reduction, MediumAI = 50%, and HardAI =
25%, for instance.