Merge branch 'master' of https://github.com/wwu-numerik/dune-stuff into threadsafe_expression

dune/stuff/la/container.hh

dune/stuff/la/container/common.hh

dune/stuff/la/container/container-interface.hh

dune/stuff/la/container/eigen.hh

dune/stuff/la/container/eigen/base.hh

dune/stuff/la/container/eigen/dense.hh

dune/stuff/la/container/eigen/sparse.hh

dune/stuff/la/container/interfaces.hh

dune/stuff/la/container/istl.hh

dune/stuff/la/container/matrix-interface.hh

dune/stuff/la/container/pattern.cc

dune/stuff/la/container/pattern.hh

dune/stuff/la/container/vector-interface-internal.hh

dune/stuff/la/container/vector-interface.hh

dune/stuff/la/solver.hh

dune/stuff/la/solver/common.hh

dune/stuff/la/solver/eigen.hh

dune/stuff/la/solver/fasp.hh

dune/stuff/la/solver/istl.hh

dune/stuff/la/solver/istl_amg.hh