Merge branch 'modernize-rod-code' into 'master'

dune/gfe/cosseratenergystiffness.hh

dune/gfe/cosseratrodenergy.hh

dune/gfe/geodesicfeassembler.hh

dune/gfe/geodesicfeassemblerwrapper.hh

dune/gfe/gramschmidtsolver.hh

dune/gfe/localfirstordermodel.hh

dune/gfe/localgeodesicfefunction.hh

dune/gfe/localprojectedfefunction.hh

dune/gfe/parallel/globalp2mapper.hh

dune/gfe/riemannianpnsolver.cc

dune/gfe/riemanniantrsolver.cc

dune/gfe/rodassembler.cc

dune/gfe/rodassembler.hh

dune/gfe/rodlocalstiffness.hh

dune/gfe/rotation.hh

dune/gfe/unitvector.hh

problems/staticrod.parset

src/cosserat-continuum.cc

src/rod3d.cc

test/CMakeLists.txt