eliminate version parameter

["Ray Denenberg, Library of Congress" <rden@loc.gov>]

Note the suggestion on the SRU list to drop the version parameter.   I
responded that doing so would take away the ability for different versions
to interoperate.   But thinking more about it more, I'm not sure.

This would take some thinking through - using different base URLs to for
different versions, and exposing the names and versions via explain, a
client would know the server version so there would never be a mismatch.

I think eliminating the version parameter makes sense.

What do you think?

--Ray