Qa fixes

* Save previous state and restore on "Go back"
* Fix regression in child content display
* Make ooyala transcript work with settings (3play api key)
This line is doing too much, it is hard to understand - can you break it down a bit more to make it esier to follow, ie something like:

```
for d in reversed(t):
  if d['step'] == step.name:
    return d['choice']
return None
```

That also removes the need to use the index, catch an exception, or remove duplicate steps from the history (which might be useful to preserve).