Add testing capabilities to build.xml (for ant)

Hi,

I've written some ant build targets to easily run the java and python tests, which I guess these might be useful to other people at some point. They're heavily based on the [examples here](http://ant.apache.org/manual/Tasks/junit.html) and [here](http://ant.apache.org/manual/Tasks/junit.html).

On a related note how do you normally run the tests?

[ I guess I should also introduce myself right? I'm David, I'm doing some work with Rizos Sakellariou at the University of Manchester and he recommended using this code for some simulations. I'm hopefully going to be doing something on scheduling workflows when you have a cap on the power usage. ]