Fixed function prototypes for driver interface functions.  Added macro PL_NOTSET for use in plsdidev() to leave specific variables unaltered by the function call.  May be supported by other functions later.
Fixed function prototypes for driver interface functions.  Added macro
PL_NOTSET for use in plsdidev() to leave specific variables unaltered by
the function call.  May be supported by other functions later.

svn path=/trunk/; revision=402

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