Another slightly less rough cut at XML based configuration. There

Another slightly less rough cut at XML based configuration.  There
is still a large reliance on the existing scripts for loopback
support, portals config, and module loading.  I'll try and resolve
some of these things after some consultation about what the best
way to do that is.

- Several minor changes were made to the DTD, we're still not
  validating against it but it should be consistent with the example.
- Simple code added for ldlm, mds, obd, ost, osc, and mdc configuration.
- Other misc support and fixes.

A local filesystem should be mountable with the net-local.xml config:

~/tests/llxmlsetup.sh net-local.xml