Metadata Generation

[Rod Widdowson]

> I was hoping to avoid having a chaining provider in the example since
> that's now optional, but I guess we can open an issue and look at adding a
> "null" provider in as a fallback later.

You actually make me realize that I haven't fully tested this. The
metadata-provider.xml can contain a <RelyingPartyGroup> file (with of course
can need not have any metadata resolvers).  At the very least I need to test
that.

I am also wondering what would happy with a resolver file which has some
content (like comments) which would get us past the crash I observed, but
had neither a <RelyingPartyGroup>, nor a <MetadataProvider>.  Making that
work would likely be a lot easier than making an absolutely empty file work.

I'll look and report back

Rod