Improved documentation for plsdev, plsdiplz, and plsesc.
Improved documentation for plsdev, plsdiplz, and plsesc.

svn path=/trunk/; revision=3532

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