Added attributes.xml

Used for telling the client about the minimum and maximum amount of points each attribute can have as well as the amount of points that need to be distributed.

The listed attributes are only used to validate the correctness of the character starting points. We could make the client use them, but that would be at the cost of internationalization.

See http://bugs.manasource.org/view.php?id=501

Depends on mana/mana#29