ISSUE-41: annotation and documentation elements as basic patterns

ISSUE-41: annotation and documentation elements as basic patterns

http://www.w3.org/2005/06/tracker/databinding/issues/41

Raised by: Paul Downey
On product: Basic

The input document makes no mention of the xs:documentation or xs:annotation
elements, and yet these are useful, in common use. I'm also 
unaware of any interoperability issues with documentation.

Note appInfo annotations may introduce issues and are in-scope for 
our Advanced patterns.

Proposal:

The Basic patterns document allows appearance of annotation
and documentation elements throughout other valid patterns, 
i.e. we allow in Basic Patterns conformant schemas:

//xs:annotation/xs:documentation/{xs:any}