Merge trunk into branch_port_the_testsuite

git-svn-id: https://svn.dealii.org/branches/branch_port_the_testsuite@31313 0785d39b-7218-0410-832d-ea1e28bc413d

diff --cc deal.II/source/base/data_out_base.cc
Simple merge

diff --cc tests/mpi/constraint_matrix_set_zero_02.mpirun=1.output
Simple merge

diff --cc tests/mpi/constraint_matrix_set_zero_02.mpirun=2.output
Simple merge

diff --cc tests/mpi/matrix_free_02.cc
Simple merge

diff --cc tests/mpi/parallel_block_vector_01.cc
Simple merge