Changed "clean" target to remove selected subdirectories: "plplot" (anticipating Alan's change), and "ti_files" (for C++ cleanup).
Changed "clean" target to remove selected subdirectories: "plplot"
(anticipating Alan's change), and "ti_files" (for C++ cleanup).

svn path=/trunk/; revision=2285

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