Added driver interface filtering to plP_text.  Call plot buffer before filtering.
Added driver interface filtering to plP_text.  Call plot buffer before
filtering.

svn path=/trunk/; revision=6290

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