Merge branch 'feature/curvedgeometry3' into 'master'

doc/geometries/ellipsoid.py

dune.module

dune/curvedsurfacegrid/CMakeLists.txt

dune/curvedsurfacegrid/backuprestore.hh

dune/curvedsurfacegrid/capabilities.hh

dune/curvedsurfacegrid/concepts.hh

dune/curvedsurfacegrid/coordfunctionimplementations.hh

dune/curvedsurfacegrid/coordprovider.hh

dune/curvedsurfacegrid/datahandle.hh

dune/curvedsurfacegrid/declaration.hh

dune/curvedsurfacegrid/entity.hh

dune/curvedsurfacegrid/entityseed.hh

dune/curvedsurfacegrid/geometry.hh

dune/curvedsurfacegrid/grid.hh

dune/curvedsurfacegrid/gridfamily.hh

dune/curvedsurfacegrid/gridfunctions/CMakeLists.txt

dune/curvedsurfacegrid/gridfunctions/analyticgridfunction.hh

...rvedsurfacegrid/gridfunctions/discretegridviewfunction.hh

.../curvedsurfacegrid/gridfunctions/ellipsoidgridfunction.hh

dune/curvedsurfacegrid/gridfunctions/gridentityset.hh