Expose convenience wrappers on interfaces

Implement custom property loader so existing code will work with skyrim property 1 and property 2 links.

2.

2. Rebuild niflib from current nifxml
3. Add support for ByteColor3 and ByteColor4 for streaming
4. Add all of the classes not currently added

This reverts commit 7f63402c.

Made various NiSkinPartition methods public, so they can be manipulated (contributed by gentle_sal, see issue #3411675).

Added method to remove match data from NiTriShapeData (contributed by gentle_sal, see issue #3411674).

Added subshape and material access to bhkConvexListShape (contributed by gentle_sal, see issue #3411666).