Added initWithGroup to GHTestGroup.
GHUnitIOSTestViewController now requires to be passed a test and its group.

setTest: was modified to setTest:group:

This is necessary to properly rerun the test. Without the group the testCase's shouldRunOnMainThread isn't called, giving different behavior from this particular rerun versus the testsuite run.
Merge remote-tracking branch 'Inferis/master'

Conflicts:
	Classes-iOS/GHUnitIOSTestViewController.m