Minor code cleanup

small cleanup in the parseAndReplay func
The select seems unnecessary here and we could just read from `tickChan`:

```go
<- tickChan

waitTime := scaleDuration(rec.Offset - lastOffset, 1.0/speed)
lastOffset = recOffset
...
```

Or, alternatively, is there a reason we can't just `time.Sleep(waitTime)` and do away with the channel altogether?