Summary
When configuring dune-grid-glue in combination with dune modules that require cmake 3.13, the old cmake_minimal_requires(VERSION 2.8.x) might cause hard to find errors in cmake, since this version requirements actually changes the behavior of cmake.
The examples are linked against all dune libraries by using target_link_dune_default_libraries. This might cause problems with alberta-grid that is not used, but raises a linker error, see #20. This MR fixes this by only linking against dunegrid.