Change limit slightly to avoid label flips at 90 and 270 degrees for slightly different floating point results.
Change limit slightly to avoid label flips at 90 and 270 degrees for slightly
different floating point results.

svn path=/trunk/; revision=3377

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot