Add support for Aura Kingdom nifs

[Candoran2]

Problem

Aura Kingdom nifs appear to have some properties that are not yet denoted in the xml.

Solution

Hexabits apparently made a number of changes to the xml (linked and somewhat discussed on niftools/nifskope#187 ), but it still needs to be seen what exactly those changes are and whether they can be integrated into the main fork.

If it is possible, then obviously do that. Here is an example of an Aura Kingdom nif for analysis and testing whether the changes to the xml are sufficient:
test.zip

If it is not possible, this issue can at least serve as a place to put down exactly why that can't happen and what the exact differences are.