Make FastAMG available from dune/istl/paamg/amg.hh and provide a define to

indicate that it is available.

[[Imported from SVN: r1893]]

dune/istl/paamg/amg.hh

@@ -16,6 +16,9 @@
 #include <dune/common/typetraits.hh>
 #include <dune/common/exceptions.hh>
 
+#define HAS_DUNE_FAST_AMG
+#include <dune/istl/paamg/fastamg.hh>
+
 namespace Dune
 {
   namespace Amg

dune/istl/paamg/test/fastamg.cc

@@ -6,7 +6,7 @@
 #include <dune/common/timer.hh>
 #include <dune/common/parallel/indexset.hh>
 #include <dune/common/collectivecommunication.hh>
-#include <dune/istl/paamg/fastamg.hh>
+#include <dune/istl/paamg/amg.hh>
 #include <dune/istl/paamg/pinfo.hh>
 #include <dune/istl/solvers.hh>
 #include <cstdlib>