Add special requirements to level requirements where they are de facto level
requirements.
For example: Tarma level 14 requires Remove Poison be studied to 27%. In order
to study Remove Poison past 20%(?), Lessen Poison must be trained to 50%. So,
Lessen Poison to 50% should be a requirement for level 14.
Making these simple changes will enable the 'train level' command to work as
intended without substantially recoding it.