Fix circleIndexFromMarkIndex function in circle timelines. Was returning wrong values and causing errors.
Fix problem where the starting breakpoint index for an explored interval was not recorded.
Revert replay-to-breakpoint to case logic on model's debuggerResumed callback instead of attaching a new callback.
Revert TimelapseIntervalTracker to tracking only mark indices and not breakpoint indices. Breakpoint tracking is much simpler when the breakpoint-hit records for a given mark index are atomic.
Record all breakpoint hits in breakpoint tracker, but only send them to data providers during breakpoint scans. Clean up code in model and breakpoint tracker. Add events for breakpoint scan start and finish to model.
Fix overview previews for breakpoint circles.