Bug fix release.

Potential breaking changes

If you use some optional dependency of dom4j (for example Jaxen, xsdlib etc.), you need to specify an explicit dependency on it in your project. They are no longer marked as a mandatory transitive dependency by dom4j.
Following SAX parser features are disabled by default in DocumentHelper.parse() for security reasons (they were enabled in previous versions):
- http://xml.org/sax/properties/external-general-entities
- http://xml.org/sax/properties/external-parameter-entities

Fixed issues

#28 Possible vulnerability of DocumentHelper.parseText() to XML injection (reported by @s0m30ne)
#34 CVS directories left in the source tree (reported by @ebourg)
#38 XMLWriter does not escape supplementary unicode characters correctly (reported by @abenkovskii)
#39 writer.writeOpen(x) doesn't write namespaces (reported by @borissmidt)
#40 concurrency problem with QNameCache (@jbennett2091)
#43 and #46 all dependencies are optional (reported by @Zardoz89 and @vmassol)
#44 SAXReader: hardcoded namespace features (reported by @philippeu)
#48 validate QNames (reported by @mario-areias)