Merge branch 'feature/avoid-calling-deprecated-size-methods' into 'master'

Avoid calling deprecated methods

This silences several compiler warnings from gcc 6.2.0 looking like this:

dune/grid/common/grid.hh:730:45: warning:
‘int Dune::OneDGrid::overlapSize(int, int) const’ is deprecated:
"overlapSize() is deprecated. Use the method on the
LevelGridView instead." [-Wdeprecated-declarations]

See merge request !107 (merged)