[Dune] Grid check

[Thimo Neubauer]

Hi,

as you may have seen I've commited a grid-test framework. Please run
./autogen.sh after the upgrade, a lot of stuff changed. The biggest
difference you'll notice is that it checks for stuff like Albert or
UG. This is only so that the self-tests can link against the
components, the library and headers are of course unchanged and will
work without external stuff as usual. So don't be alarmed :)

I've added small notices to stress this point so that later Dune-users
will not try to provide a lot of information to configure which is not
needed. Please tell me if the messages are confusing

The test-code in grid/test/gridcheck.cc just uses the checkIF-method
for now which seems to suffice for the start: there are already some
failures. Nevertheless feel free to add more checks for topoligical or
geometric consistency. I myself will try to transfer stuff from
duneapps/tester/gridcheck later on.

Cheers
   Thimo