Updated license text in remaining files.  Short text in all files except niflib.h, and year updated to 2006.

Incorporated defines into the h and cpp files I'd already made for NiNode, NiObjectNET, and NiAVObject.

Noticed that I had forgot to include NiObject.cpp in my last commit... unfortunately I've already started splitting off classes into their own files so that's included in this commit as well.
I also noticed that I never implemented the member functions of Ref!  I still haven't, but I was just surprised it's been compiling without complaint.

Got rid of globals for good measure.

Temporarily disabled build of the Python wrapper (gives lot's of errors at the moment, will fix later).

Updated SConstruct file.

Default floats have trailing "f".
Template pointers are now really pointers.
Updated #include's.
Added #endif.

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.