[XML-SIG] expat namespace_separator in Python 2.1

[Daniel "eikeon" Krech]

>   I added the check that a string passed as the namespace_separator
> would be either omitted, None, or of length 1.  I don't understand why
> you would want it to be of length 0 -- were you expecting parsing
> without namespaces?  Is there a reason to pass namespace_separator as
> an empty string rather than None, or just omit it?

If we pass in None or omit it ends up parsing without namespaces, or at
least the names we are getting are of the form prefix:localname. We do want
namespaces, just with no separator between the namespace and the local name.
     [For <p:bar xmlns="foo"/> in our application (of the parser) we would
like to receive names in the form foobar. Passing in None yields p:bar]

-eikeon