read_network parameter is ignored, so read_network is always disallowed

[Silvio Tomatis]

In rules.py (http://codespeak.net/svn/z3/xdv/trunk/lib/xdv/rules.py) in functions expand_themes and add_theme there is no check if read_network is True, and this results in an always disabled transform.

[Nils Fredrik Gjerull (nfg)]

This is a simple patch that checks the read_network parameter. I have run the test suite on my computer, and tested it with my use case. I run on an Ubuntu 10.04, using lxml-2.3beta1 with libxslt-1.1.26 and libxml2-2.7.6.