text: Title: Problem with learner_time_limit
  Body: Hi Piotr:
  
  Thanks for the changes made in the ner version.  I'm now getting an error when setting learner_time_limit.  Did you take this option out?  I see in your code that you are setting it automatically as a function of total_time_limit.  Can this be the behavior only if learner_time_limit is None?
    