XMLParser: issue #26; return API version parsed from response
File: cloѕe #64; keep track of "partial" File objects

- Partial File objects would be created when a "latestfiles" request
  is made for example
XMLParser: issue #46; parse a 'latestfiles' request

- Return the list of files to a 'latestfiles' request
idgames_db_dump: issue #46; read API version from 'latestfiles' query