calling fixAdjustedStart in get currentTime() can cause infinite loop

get currentTime can result in a call to fixAdjustedStack when 

```
if (this.rawCurrentTime < this.offset) {
      this.fixAdjustedStart(this.offset);
  }
```

however `ffixAdjustedStart` can then again call `currentTime` in order to fire the seek event.. this will result in a `Maximum call stack size exceeded`

This seems to happen rarely when selecting tight regions.