This patch adds 3 properties to methodcaller objects for inspecting the object at runtime:

1. 'name': the name of the method to call
2. 'args': the position arguments to pass to the method
3. 'keywords': the keyword arguments to pass to the method

args and keywords act like functools.partial (that is why I did not name it kwargs).

I noticed that recently the repr changed to expose this information which helps in the debugging use case; however, this allows us to use the methodcaller to maybe construct a new methodcaller with different args, or call a different method with the same args.