Put in a DocType declaration to get rid of one SVG 1.1 validator warning.
Put in a DocType declaration to get rid of one SVG 1.1 validator warning.

svn path=/trunk/; revision=8883

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