Fixed batting average handling for players who only played one year
Fixed broken spec from last change
Added SluggingPercentage calculator
Fix slugging percentage spec to check all hit stats
Added TripleCrown calculator
Renamed calculators to make them easier to find on the filesystem
Fixed 'no winner' output for triple crown calculator
Rake tasks CLI for saber stats
Fix TripleCrownCalculator to handle tied stats
Fixed TripleCrownCalculator to ignore players with less than 200 at_bats
Fix TripleCrownCalculator to work when no one has the highest batting average
Added README