build error - Extension.java

```
com\topologi\diffx\Extension.java:159: newInstance() in 
javax.xml.parsers.DocumentBuilderFactory
cannot be applied to (java.lang.String,java.lang.ClassLoader)
    [javac]         : DocumentBuilderFactory.newInstance(factory, Extension.class.getClassLoader());  

building with Java 1.7

```

Original issue reported on code.google.com by `jhar...@gmail.com` on 28 May 2013 at 3:38
