[Commons-l] SVG validity checks

[Brion Vibber]

While reviewing some other code, I went in and started ripping up some 
of the file type & validity checks in MediaWiki's upload system, as 
they've been driving me nuts for some time.

One quick subproject was tossing in an XML well-formedness check for SVG 
files. For the curious, here's a report on the invalid files I 
encountered while testing this with files from Commons:

http://meta.wikimedia.org/wiki/SVG_validity_checks

-- brion vibber (brion @ wikimedia.org)