made changes to the complexshape to support dismember partitions. still need to add support for merging with dismember partitions

started adding support for BSDismemberSkinInstance.h in the complex shape. so far nothing is functional but at first glance it seems pretty straightforward enough

added support to read the nif header without reading the entire file. useful to check what kind of importer should be used to read the file.

added support for skyrim and added some new ways to check the user version of a nif file to check if it's a skyrim file.

updated the BSLightingShaderProperty.cpp and BSLightingShaderProperty.h to add support for editing those objects

added a new overload for the AddInterpolatorMethod in the NiControllerSequence class to fix a bug when it would export the string pallete for fallout 3 nif versions.

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).

Use single root for nif in WriteNifTree and ResolveMissingLinkStack, to make interface consistent with the rest of niflib.