If an async test has timed-out, there could still be some expectations
that are scheduled to run after the fact in which case curerntSpec will
be null. Rather than the type error that would result, we now indicate
that 'expect' was used at an unexpected time.
This also helps cases where an 'expect' is being used at a top-level,
showing an error message in the console for this case as well.
[fixes#602]
- QueueRunner now responsible for timing out async specs instead of
Spec
- Make sure only spec functions are timeoutable and not suites (due to
the refactor)
