MediaWiki: handle self-closing ref tags and more general <ref> syntax

[GoogleCodeExporter]

e.g. <ref name="foo" />

also need to handle whitespace variation and missing quotes, and a wider set of 
allowable characters in the name than just alphanum. e.g.

<ref name = foo_bar >
<ref name="Foo bar baz!">

Original issue reported on code.google.com by matt...@swiftkey.com on 28 Jun 2013 at 9:51