Fix support for contour lines in plotfc3d() and mesh coloring in plot3d().
Fix support for contour lines in plotfc3d() and mesh coloring in plot3d().

svn path=/trunk/; revision=3993

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