Added flag to be set by driver to indicate whether TK or DP style communication is being used.
Added flag to be set by driver to indicate whether TK or DP style
communication is being used.

svn path=/trunk/; revision=638

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