Log Message:
Update to Grace 5.1.23

Changes in 5.1.23

  Bug fixes
 * [ES] removed *86 specific optimizations (rep. #2154)
 * [ES] renamed RMS per cent error -> relative error (rep. #2192)
 * [ES] a workaround for a bug in recent Xorg not releasing grab of popup menus
 * [ES] accept -graphtype chart instead of bar. List possible values in the
        help output
 * [TK] fix building against png-1.5
 * [SM] a grace_np fix
 * [ES] IsoLatin5.enc was not included in the distribution