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/H5Block/fields.c

@@ -1,4 +1,14 @@
+/*
+  Copyright (c) 2006-2017, The Regents of the University of California,
+  through Lawrence Berkeley National Laboratory (subject to receipt of any
+  required approvals from the U.S. Dept. of Energy) and the Paul Scherrer
+  Institut (Switzerland).  All rights reserved.
+
+  License: see file COPYING in top level of source distribution.
+*/
+
 #include <H5hut.h>
+#include "examples.h"
 
 #define XSIZE		8
 #define YSIZE		8