XML checking broken in py3.3

[Curtis Hovey]

The namespace ignorance rule for specialised parsers is broken in Ubuntu Saucy. The py 3.3 always defines xml.ElementTree, then redefines it with ctree. The rules to replace ElementTree.XMLParser with an expat parser fail because the internal API is different.

The quickest fix would be to define a new XMLParser based on expat and pass it to the fast feeder. Pocket-lint emphasises well-formedness and consistency; the complect validation rules are not needed.

The ideal solution is setup a parser that only checks namespaces as needed and always checks the common set of entities. The solution must work with Py3.3 and Py2.7 -- not likely to happen.