Deprecated baseCategoryValue and changed its implementation to defer to
shortCategoryValue

The previous implementation of baseCategoryValue made the assumption
that 'O' was always the element added to the domain, which is not
generally true. Rather than remove the method completely and break
things downstream, I've deprecated it and changed the implementation to
match shortCategoryValue.
deprecate shortCategoryValue, change implementation of baseCategoryValue to that of shortCategoryValue
Merge pull request #214 from strubell/master

Replace shortCategoryValue with baseCategoryValue, deprecate