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).

Added documentation to IControllerSequence.

I made some little update to the script to make sure the libs are built in the proper order, and I also commented out the niflyze build string since it resides in another folder

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

* Support for all ten NiStringPalette offsets.
* There's still a problem with NiStringPalette: apparently the C++ string type does not allow null characters? ... Maybe we can try to find a workaround in the string reader function.

* Changed the radius algorithm.

Now the calculated center & radius values should correspond to the values found in official NIF files.

Brought NiControllerSequence up to date with DocSys, but commented out interface functions for later implementation.

Block implementation is current with DocSys again.

Small changes to constness of some functions.