Refactor logic contained within _GrailsTest into 2 classes: GrailsProjectTestCompiler and GrailsProjectTestRunner
upgrade to Groovy 2.1.0 final
allow running of functional tests against existing background server
refactor login in _GrailsClean into new class GrailsProjectCleaner
use new GrailsProjectCleaner class to implement testOptions.clean functionality