completed example 20 with plimagefr calls.  Needs PDL-Graphics-PLplot-0.42
completed example 20 with plimagefr calls.  Needs PDL-Graphics-PLplot-0.42

svn path=/trunk/; revision=9038

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