SpecializedSkillScore w/tests

Also, I think I approached skills totally wrong re: standard / focus /
specialized skills since at least for local knowledge, both are possible
in the same skill. e.g. Local Knowledge [Seattle] {Restaurants}.

The current design was in theory easier since it locked things down, but
it's actually ending up fairly complicated. The case above might actually
really simplify things, but it is also a huge redesign.