Slightly cleaner fix to plfill. Also fix a typo bug in plfill3 which would have caused a crash for large numbers of points. 
Slightly cleaner fix to plfill. Also fix a typo bug in plfill3 which would have caused a crash for large numbers of points. 


svn path=/trunk/; revision=11846

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