Rename ValuesAsArrayOfStrings to StringValues; this method now raises a TypeMismatchException when some array element does not inherit from NSString instead of skipping; fix several occurrences of a bug in NSFontManager in which NSArray.VariantValue was being returned instead of a String array.
Remove commented-out code.
Clean up code here and there.
Rewrite NSString; conversion to and from String is now implemented.  Changes to this class required changing other code as well.