Added stringsearch1 benchmark

    * Makefile.am: Added stringsearch1 benchmark
    * Makefile.in: Regenerated
    * configure: Regenerated
    * configure.ac: Added stringsearch1 benchmark
    * src/stringsearch1/Makefile.am: Added stringsearch1 benchmark
    * src/stringsearch1/Makefile.in: Regenerated
    * src/stringsearch1/fast.fwd.inc.c: Added stringsearch1 benchmark
    * src/stringsearch1/fast.rev.d12.c: Added stringsearch1 benchmark
    * src/stringsearch1/stringsearch1.c: Added stringsearch1 benchmark