two failing tests
something passing, but not ideal (arigo)
a better way - pass function to be called as self (argio)
fix test
failing test for method callbacks
convert_function works for methods just fine
use identity_dict for _applevel_by_obj mapping
use identity dict only for unhashable objects
failing test for exceptions in callbacks
raising exceptions from callbacks
Merge pull request #7 from rguillebert/callbacks

Basic support for callbacks