Check for file change after each trial

[moi90]

This way, changes can be incorporated earlier.

[moi90]

experiments.py was changed, reloading...                                                                                                                                                                           
terminate called after throwing an instance of 'std::runtime_error'                                                                                                                                                
  what():  generic_type: cannot initialize type "DistAutogradContext": an object with that name is already defined                                                                                                 
Aborted (core dumped)