Reconsidered search order.. now check of install dir is done after the check of PL_LIBRARY and the standard tcl extension location.  This is so that you cal always use PL_LIBRARY to get the behavior you want.  Also restructured search logic to be more flexible (wrt rearrangement) and clear.
Reconsidered search order.. now check of install dir is done after the
check of PL_LIBRARY and the standard tcl extension location.  This is so
that you cal always use PL_LIBRARY to get the behavior you want.  Also
restructured search logic to be more flexible (wrt rearrangement) and
clear.

svn path=/trunk/; revision=3981

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