Reorganize examples so that there is only one standalone source file per example.
Reorganize examples so that there is only one standalone source file per
example.

include_directories introduced to allow compilation of more substantial
example code (not just a driver) that "with"ed plplot and plplotthin.

svn path=/trunk/; revision=7399

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