Nations: Reworks nations.py to use the field 700__w

* Changes nations.py to use the field 700__w for the nation
  counting

* Moves NATIONS_DEFAULT_MAP to utils.py

Signed-off-by: Martin Vesper <martin.vesper@cern.ch>
Merge pull request #15 from mvesper/nations

Nations: Reworks nations.py to use the field 700__w