1. It was assumed that no CDATA nodes were put between XML elements.
But the generated hint XML files had newlines to pretty-print the XML.
The current fix ignores every CDATA nodes. Maybe it should just ignore the
ones made of blancks.
2. Tree-structured hints were not parsed correctly (the coe was simply
wrong). Trivially fixed.
Open issue: my code is full of "assert false". Should it raise exceptions
instead? I firmly think so.