Added whetstone benchmark

    * Makefile.am: Added whetstone benchmark
    * Makefile.in: Regenerated
    * configure: Regenerated
    * configure.ac: Added whetstone benchmark
    * src/whetstone/Makefile.am: Added whetstone benchmark
    * src/whetstone/Makefile.in: Added whetstone benchmark
    * src/whetstone/whetstone.c: Added whetstone benchmark