[Python-ideas] Make Difflib example callable as module __main__

[Dan Colish]

Hey,

I was reading over the difflib docs this morning and when I got to the
bottom, I expected, probably due to lack of coffee, that the example
would be callable as the module from the command line. There are already
a number of modules which export command line functionality, ie.
unittest, and I thought it would be great if difflib module offered the
same. The code is pretty much there in the example from the
documentation. It would just need to be included in the module itself.

--Dan