[cmake] Use file-glob to gather headers to install

dune/foamgrid/foamgrid/CMakeLists.txt

-#install headers
-install(FILES foamgrid.cc
-              foamgridedge.hh
-              foamgridelements.hh
-              foamgridentity.hh
-              foamgridentitypointer.hh
-              foamgridentityseed.hh
-              foamgridfactory.hh
-              foamgridgeometry.hh
-              foamgridhierarchiciterator.hh
-              foamgridindexsets.hh
-              foamgridintersectioniterators.hh
-              foamgridintersections.hh
-              foamgridleafiterator.hh
-              foamgridleveliterator.hh
-              foamgridnulliteratorfactory.hh
-              foamgridvertex.hh
-         DESTINATION include/dune/foamgrid/foamgrid)
+# install headers
+file(GLOB DUNE_FOAMGRID_HEADERS *.hh)
+install(FILES foamgrid.cc ${DUNE_FOAMGRID_HEADERS}
+        DESTINATION include/dune/foamgrid/foamgrid)