Updated timelines tests to be more robust

* Timelines tests were literally a one stop hit and did not account for
  any delay in events being processed. This has been rectified with a
  wait_for step which tries for 60 seconds to find events, navigating to
  the page using a local nav_step() function.
* The toolbar being greyed out was never an expected even. This has now
  been rectified and is included as part of the invocation of the local
  nav_step() function. If the toolbar is greyed out then it will fail
  the wait_for with 0 events, which is the expected fail condition for
  the loop.
* There was opportunity for some DRY cleanup, which could be extended
  further. The event counting routines have bene broken out into a
  count_events function.