Cleaning up Damage
Modifiables Rock

Developed notion of a Modifiable - It is a Integer  (but could be
anything - see TODO)  score associated with an enum type.  There also is
a modifier type which allows these modifiers to stack.  This basically
replaced Attributes, Skills, and Defenses.

TODO
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Make modifiers added with events?
Abstract Modifiers away from ints - modifiers of whatever - float,
double, boolean