Merge pull request #3881 from bangerth/adjust-copyright-years

Adjust copyright years.

diff --cc include/deal.II/base/quadrature_point_data.h
Simple merge

diff --cc include/deal.II/dofs/dof_handler.h
Simple merge

diff --cc include/deal.II/fe/fe.h
Simple merge

diff --cc include/deal.II/grid/tria.h
Simple merge

diff --cc include/deal.II/lac/block_linear_operator.h
Simple merge

diff --cc include/deal.II/lac/linear_operator.h
Simple merge

diff --cc include/deal.II/lac/precondition.h
Simple merge

diff --cc include/deal.II/lac/trilinos_block_sparse_matrix.h
Simple merge

diff --cc include/deal.II/matrix_free/operators.h
Simple merge