Added support for running buster tests with PhantomJS

It was great to find this maven-plugin for BusterJS, great work!. 

We added support for running the tests with no buster server already running and running the tests against Phantomjs. So that it is possible to run the buster tests during the maven build on a CI server where there are no browser.

Also changed the goal to test, so buster:test, more inline with what you write on the command line if you want to run buster tests.

Please let me know if there are anything you want different.

Thanks again!

Peter