Eigen: fold remaining OpenNL code into intern/eigen.

CMakeLists.txt

SConstruct

build_files/cmake/cmake_static_check_clang_array.py

build_files/cmake/cmake_static_check_cppcheck.py

build_files/cmake/cmake_static_check_smatch.py

build_files/cmake/cmake_static_check_sparse.py

build_files/cmake/cmake_static_check_splint.py

build_files/cmake/config/blender_full.cmake

build_files/cmake/config/blender_lite.cmake

build_files/cmake/macros.cmake

doc/doxygen/doxygen.intern.h

extern/CMakeLists.txt

extern/SConscript

extern/colamd/CMakeLists.txt

extern/colamd/Doc/ChangeLog

extern/colamd/Doc/lesser.txt

extern/colamd/Include/UFconfig.h

extern/colamd/Include/colamd.h

extern/colamd/README.txt

extern/colamd/SConscript