add legal and other meta information

kwant/graph/c_slicer/slicer.cc

kwant/graph/c_slicer/slicer.h

kwant/graph/core.pxd

kwant/graph/core.pyx

kwant/graph/defs.h

kwant/graph/defs.pxd

kwant/graph/defs.py

kwant/graph/dissection.py

kwant/graph/scotch.pyx

kwant/graph/slicer.pyx

kwant/graph/tests/test_core.py

kwant/graph/tests/test_dissection.py

kwant/graph/tests/test_scotch.py

kwant/graph/tests/test_slicer.py

kwant/graph/tests/test_utils.py

kwant/graph/utils.pyx

kwant/lattice.py

kwant/linalg/__init__.py

kwant/linalg/_mumps.pyx

kwant/linalg/cmumps.pxd