fix recognition of source attribute in annotations

RelaxNG was rejecting this because the schema definition:

  <attribute name="source">

was being expanded into:

  <name ns="http://www.w3.org/2001/XMLSchema">source</name>

due to inheriting the namespace on the root grammar element.  This is
incorrect: attributes in XSD are unqualified and therefore have an
absent namespace.
complete wildcard verification on annotation sub-elements

An earlier commit removed the improper rejection of elements in the XSD
namespace from within documentation and appinfo elements.  This
completes that by adding a rejection of attributes in the XSD
namespace, as specified in the SfS.

For the record (since it was discovered too late): The earlier fix broke
Jing validations due to:

  https://code.google.com/p/jing-trang/issues/detail?id=178

which explains the "Changed to avoid conflicting ID types" comment from
2004.  Since Jing is being pedantic, I'm not changing that back.
fix attribute namespaces

Extend the earlier fix by ensuring that all attribute names are
specified to have no namespace rather than inheriting the XSD
namespace.  The SfS has elementFormDefault="qualified" so element names
should inherit the default (target) namespace.