Roman numeral test

I've added something to try to address my action from last week:

  ACTION DaveB: make 'XXI'^^:romanNumeral  = 21 and points nearby into 
  test cases (or ask questions in email).

See:

http://www.w3.org/2001/sw/DataAccess/tests/data/ValueTesting/roman.rq
http://www.w3.org/2001/sw/DataAccess/tests/data/ValueTesting/roman.n3
http://www.w3.org/2001/sw/DataAccess/tests/data/ValueTesting/roman-result.n3

I'm not sure if it's quite what's wanted as you could just do

 SELECT *
 WHERE { anything you like.
         FILTER ( 'XXI'^^rome:Numeral = 21 )
 }

but instead I put the roman numeral constant in the data and the 21 in
the query.

Dave