Solve some bad calls to plcont which were wreaking havoc with the results.
Solve some bad calls to plcont which were wreaking havoc with the results.

svn path=/trunk/; revision=6600

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