Comment 2 for bug 1123016

Here is a proposal to extend xqxq:

declare function xqxq:query-plan($query-key as xs:anyURI) as xs:base64Binary external;

declare function xqxq:load-from-query-plan($plan as xs:base64Binary) as xs:anyURI) external;

declare function xqxq:load-from-query-plan($plan as xs:base64Binary as xs:anyURI, $resolver as item()?, $mapper as item()?) external;

- I'm sure there are better names for the function.
- query-plan should return a streamable base64Binary
- load-from-query-plan should work on streamable and non-streamable base64Binaries