Unify usage of multiple callbacks
🚀 Feature
Simplified API, with callbacks... as e.g. Keras did, pass just list of callbacks to be executed and Trainer will call then when needed instead of having them specified

  
    
      pytorch-lightning/pytorch_lightning/trainer/trainer.py
    
    
        Lines 65 to 66
      in
      b104052
    
  
  
    

        
          
           checkpoint_callback=True, 
        

        
          
           early_stop_callback=None, 
        
    
  


mentioned also in #825 (comment)