Block implementation is current with DocSys again.

Small changes to constness of some functions.

Simplified the ITriShapeData and ITriStripsData interfaces slightly.

reverted skeleton root calculation (now GetParent() tries to return a node the old strategy works again, and actually it even works better :-) )

* fixed skeleton root calculation

workaround in SkeletonRootAttr to extract correct skeleton root also for BabelFish.nif; probably needs some more testing

Created classes for all new 20.0.0.4 blocks.
Re-implemented NiTexturingProperty as a data-style block.  Still needs an interface so is currently uncontrollable.

Fixed a bug that was causing a Segmentation Fault when Nif files that had NiSourceTexture blocks were read by code compiled with GCC.

Implemented GetLinks() functions for NiBoneLODController and NiControllerSequence blocks so that their internal links will be followed when writing files.

Several fixes to blocks that didn�t have arrays expanded in the DocSys.
DocSys is now fully implemented, so all versions 4.x and 10.x files that it supports are now supported.
Fixed one warning in GCC.