C examples:

- define dummy MPI macros to be used in serial compilation, closing #10
- cleanup some "unused variable" warnings
- fix some format warnings, using C99 format macros

examples/H5Part/write_setview.c

@@ -8,6 +8,7 @@
 */
 
 #include "H5hut.h"
+#include "examples.h"
 
 // name of output file
 const char* fname = "example_setview.h5";
@@ -28,8 +29,6 @@ main (
         // initialize MPI & H5hut
         MPI_Init (&argc, &argv);
         MPI_Comm comm = MPI_COMM_WORLD;
-        int comm_size = 1;
-        MPI_Comm_size (comm, &comm_size);
         int comm_rank = 0;
         MPI_Comm_rank (comm, &comm_rank);
         H5AbortOnError ();