BAtlas ID update: add map 37, various fixes

Latest XML in http://atlantides.org/batlas/

I've added a read-me file, as well as text files containing diffs between previous and current versions of the individual xml files. The readme file says:

  • altered citations so that location descriptions for unnamed features are enclosed in parentheses
  • fixed bug in processing of fragmentary, unreconstructable geognames so that lacunae are signaled with parentheses around ellipsis (...) instead of ellipsis alone; also, mark them correctly as completeness="non-reconstructable" instead of type="variant"
  • remove inverted quotes from geogname variants and instead mark them as accuracy="inaccurate"
  • handle group notation in location description for unnamed features like aqueducts and villas so that, e.g., Map-by-Map directory entry in Aqueducts for map 22 C5 with location description "Nicopolis ad Istrum (2)" becomes "aqueduct-group-nicopolis-ad-istrum-22-c5" instead of "aqueduct-nicopolis-ad-istrum-2-22-c5"; this also adds a new element child of indicating the number of features associated with the group.