[libvirt] Generic processing of xml data

There are some changes made to the conf code to handle some new tags like <title> or to add some "metadata" to a domain description in the last days. I'm wondering if there is a more generic (read better) way to handle those extra data in xml config elements. I think it would be far more reasonable to use xml namespaces to enable libvirt to differentiate between config options which it has to process and data which are unknown to libvirt and thus are only stored without any further processing. This distinction could then by easily used for expansions like the <title>-tag, to store the x- and y-position of a guest in a graphical visualization of virtual networks, to add some names of administrators which are responsible for the guests, to add some hints to interfaces concerning quality of service, etc... I don't know how complex such in implementation would be but I think it would be worth the effort. Hendrik Schwartke