Add support for  shading() in surfl(). Use the new plmeshc() and plot3d() API entries. Use new 'opt' values for above API entries.
Add support for  shading() in surfl().
Use the new plmeshc() and plot3d() API entries.
Use new 'opt' values for above API entries.

svn path=/trunk/; revision=4178

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