serif ==> italic to distinguish visual results more clearly when a font is changed in the middle of a superscript/subscript level.
serif ==> italic to distinguish visual results more clearly when a font
is changed in the middle of a superscript/subscript level.

Note that -dev qtwidget changes to the italic font at the correct
point in the string.  -dev xcairo changes to the italic font for the
_entire_ string (which demonstrates a current cairo bug).


svn path=/trunk/; revision=11789

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