updates license header

cpp/Lagrange_polys.cpp

cpp/Lagrange_polys.hpp

cpp/base.hpp

cpp/bfps_timer.hpp

cpp/fftw_interface.hpp

cpp/fftw_tools.cpp

cpp/fftw_tools.hpp

cpp/field.cpp

cpp/field.hpp

cpp/field_binary_IO.cpp

cpp/field_binary_IO.hpp

cpp/field_layout.cpp

cpp/field_layout.hpp

cpp/hdf5_tools.hpp

cpp/kspace.cpp

cpp/kspace.hpp

cpp/scope_timer.hpp

cpp/spline_n1.cpp

cpp/spline_n1.hpp

cpp/spline_n10.cpp