Log Message:
py-lxml: updated to 4.3.0

Features added
* The module lxml.sax is compiled using Cython in order to speed it up.
* lxml.sax.ElementTreeProducer now preserves the namespace prefixes. If two \ 
prefixes point to the same URI, the first prefix in alphabetical order is used. \ 
Patch by Lennart Regebro.
* Updated ISO-Schematron implementation to 2013 version (now MIT licensed) and \ 
the corresponding schema to the 2016 version (with optional “properties”).

Other changes
* Support for Python 2.6 and 3.3 was removed. Patch by hugovk.
* The minimum dependency versions were raised to libxml2 2.9.2 and libxslt \ 
1.1.27, which were released in 2014 and 2012 respectively.
* Built with Cython 0.29.2.