* test/testcase.vala (TestCase): Make the test case's main loop
  accessible to subclasses so they are using the same one we are.
  (TestCase::async_result): Use GLib main context rather than GTK+ main
  loop so that test cases with async methods work even when GTK+ not
  present.
  (TestCase::async_complete): Ensure the main loop is woken when an async
  test completes so the test case doesn't block if it loses the race with
  async_result();