Comment 4 for bug 1294784

This patch adds a sanity check on SVG input in style.cpp that clamps the minimum size font to 1e-32. That seems to resolve this bug.

I never found the location where the font size of zero caused the other elements not to be drawn, but suspect it may have resulted from an unhandled divide by zero in some location involving scaling, with the font size directly or indirectly in the denominator.