Split YaspGrid tests into more tests and introduce parallel testing

The previous YaspGrid test was a single test which took ages to compile and run.

This branch remodels the Yasp testing suite to achieve the following:

• Split the different parts into separate tests
• Introduce a more sophisticated communication test
• Test periodic grids
• Do parallel testing through dune_add_test
• Test with -Wall -Werror!!!
• Have tests with and without deprecations!

dune/grid/test/yasp/CMakeLists.txt

+# Add all tests without deprecations
+dune_add_test(NAME test-yaspgrid-backuprestore-equidistant
+              SOURCES test-yaspgrid-backuprestore-equidistant.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )
+
+dune_add_test(NAME test-yaspgrid-backuprestore-equidistantoffset
+              SOURCES test-yaspgrid-backuprestore-equidistantoffset.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )
+
+dune_add_test(NAME test-yaspgrid-backuprestore-tensor
+              SOURCES test-yaspgrid-backuprestore-tensor.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )
+
+dune_add_test(NAME test-yaspgrid-tensorgridfactory
+              SOURCES test-yaspgrid-tensorgridfactory.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )
+
+dune_add_test(NAME test-yaspgrid-yaspfactory-1d
+              SOURCES test-yaspgrid-yaspfactory-1d.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )
+
+dune_add_test(NAME test-yaspgrid-yaspfactory-2d
+              SOURCES test-yaspgrid-yaspfactory-2d.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )
+
+dune_add_test(NAME test-yaspgrid-yaspfactory-3d
+              SOURCES test-yaspgrid-yaspfactory-3d.cc
+              MPI_RANKS 1 2
+              TIMEOUT 666
+              )