[Cataclysm] Visit trainer only if there are spells to be trained

Currently the bot may visit a class trainer even if there is no spell to be trained. It would be nice if in Cataclysm the bot would take into account the spell book information while deciding if it should visit the trainer or not:

I guess the training state could be cancelled via "robotManager.Events.FiniteStateMachineEvents.OnBeforeCheckIfNeedToRunState", but I don't see any method in the Spell/SpellInfo/SpellManger that could return if a method is 'learnable' - is this something that can be added to the API ? (and maybe throw an error on other expansions, since WoTLK and lower would need static lists, and MoP and higher don't have training anymore).