Give a tspan element a dy and/or dx attribute.

The text position should be advanced by the specified lengths. Instead, the content of the tspan is rendered at position 0 on the respective coordinate, as both dx/dy and the current text position are ignored.

Observed in SVG Web version 2010-08-10 “Owlephant”

Issue 439 - tspan without x,y attibutes positioned incorrectly - is related, since implementing dx/dy requires respecting the current text position.

See the attached file for a reduced test case. See <http://frankbruder.fr.ohost.de/tragicomics/?+svgweb;title=expertise&gt; for a webcomic which commonly uses x="0" dy="1em" to implement multi-lined text.

I added the missing support for dy to issue 443 some time ago, they may be merged http://code.google.com/p/svgweb/issues/detail?id=443