* build will call nifxml_swig.py and nifxml_niflib.py
* removed legacy swig interface generating code from niflib_niflib.py
* removed pyniflib.i_old and obj_common.i since they are no longer used
* set eol-style to native on some files in niflib/src/gen for linux compatibility
* removed svn:externals property on contrib/niflib/pywrap as it is no longer needed