Moved things around and updated xml_extract.h so that everything compiles again.  Other than NIF_Blocks.h/cpp which will be removed in the future, of course.

Implemented some of the object hierarchy the new way in nif_objects.h and started updating niflib.cpp.

Removed interfaces and moved documentation to real classes.  NIF_Blocks.cpp and niflib.cpp no longer compile.

Begun work on the new type of Attributes which store pointers to their data rather than the data itself.  Moved some code to new files to fix problems with cross-includes.
Need to decide what to do about TexSource, a struct in the external interface that should have a link in it.

Removed split-tree functions from public interface.
Restored WriteFileGroup.

Added SplitKfTree and SplitNifTree functions to the interface. SplitNifTree is implemented for Morrowind only (copied code from old WriteNifTree function), SplitKfTree is not implemented at all. These two functions replace WriteFileGroup.

Updated MergeNifTrees to handle some cross references (skin blocks).  Other blocks with cross references can be added by overloading the ABlock::ReassignCrossRefs function.

MergeActions: read NIF file and all KF files (TODO: merge them as well).

Fixed ReadString function so that it can read strings with \0 characters in them.

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.

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.

Some internal changes.
Fixed destructor of NiControllerSequence to remove itself as the parent of blocks it points to if it is destroyed.

Implemented NiControllerSequence block and interface.