New attribute for special items.

[PM]

For quest or unique items, such as the Heretic MacGuffins, Qianlong archcannon, stargate rods, and id chips, there should be a new attribute, say... macGuffin, majorItem, plotItem, priorityItem, or questItem. These are the sort of items that should be looted first. I would have all of my mods that feature automatic looting take these items first, but that would require more code than it is worth. An attribute that only critical/quest items share would be helpful.