When a reference document uses a non-standard namespace prefix for the
WordprocessingML namespace (e.g. `ns0` instead of `w`), `sectPr` elements
copied from the reference would retain the non-`w` prefix, producing
malformed XML in the output document. Similarly,
`extractPageLayout` only matched elements with prefix `w`, missing
`sectPr` elements with other prefixes. This is fixed by matching on the
namespace URI rather than the prefix, and normalizing the prefix to `w`
on all elements and attributes copied from reference-doc `sectPr`.
Some new tests have been added, and the test suite has been streamlined
using helper functions.
Robertas
06af643730