Add PLFLT_MIN/MAX definition. Add plgriddata() prototype and the defines of the several gridding algorithm types.
Add PLFLT_MIN/MAX definition.
Add plgriddata() prototype and the defines of the several gridding algorithm types.

svn path=/trunk/; revision=4474

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