Add support for BPO/BPC Differentiation

[AndreasPK]

The Asset api now enables us to differentiate BPO's and BPC's (http://community.eveonline.com/news/dev-blogs/2324)

However evelink doesn't provide this information currently. The information is encoded in the rawQuantity which is only present when required,

Example rows:

<row itemID="374680079" locationID="60012577" typeID="973" quantity="1" flag="4" singleton="1" rawQuantity="-2"/>
<row itemID="390029855" locationID="60012577" typeID="16243" quantity="1" flag="4" singleton="1" rawQuantity="-1"/>

From eve-dev:

New field - rawQuantity

Items in the AssetList (and ContractItems) now include a rawQuantity attribute if the quantity in the DB is negative. Negative quantities are in fact codes, -1 indicates that the item is a singleton (non-stackable). If the item happens to be a Blueprint, -1 is an Original and -2 is a Blueprint Copy. For further information about negative quantities see this devblog http://www.eveonline.com/devblog.asp?a=blog&nbid=2324