version 0.9.5 - API CHANGE
 Instead of anything starting with `xql:` will need to use AS `xql:raw`
 to insert raw XML. Anything starting with `xql:` is taken as directive.

 Adding a node with a CDATA section was a big hassle before v0.9.5. You 
 needed to do xql_agg(title, xql_element("description", xql_cdata(desc))). 
 This is slow and generally sucks. Therefor a new directive `xql:cdata` is
 implemented, allowing xql_agg(title, desc AS `xql:cdata:description`).