Stable schema locations

[Tom Zeller]

> The follow-on to the earlier thread about the schema lookup is where we
> want to point remote references to the schemas in the documents and
> imports. There seem to be two obvious options:
>
> - directly into svn
> - putting them up on the web site

I suggest emulating Spring and providing schemas via
'http://shibboleth.net/schema/'.

If serving static documents is cumbersome, maybe we could redirect to
Subversion or Nexus, but that might be too complicated.