svgclean.xsl: new XSL stylesheet to help clean up our inkscape mess

svgclean.xsl: new XSL stylesheet to help clean up our inkscape mess

There are a few more cleanup/minimization opportunities left in our
SVG, even after it has been scoured. For example, inkscape wraps all
of its text in redundant <tspan> elements, even when the parent <text>
has the same style as the sole <tspan>. We'd like to remove those, to
simplify the code and save space.

XSLT can do this. This new stylesheet can do this. We add it now, in
preparation for yet another SVG processing phase.