Use PhantomJS as the default test browser

Uses PhantomJS as the default test browser.

Also fixed the bootstrap of the Chrome test for machines that have the chromdriver on their PATH and don't have the system variable set.

The default browser type is overwriteable by using `mvn test -P integrationtests -Dtest.browser=FIREFOX` for example.

Funny enough, it is *slower* than testing with FireFox. The upshot is mainly that you don't have the browser popping over your screen all the time.