Hatcher class missing str() method

[andenacitelli]

When trying to call str() on a Hatcher, it errors out with the following message:

return 'BaseHatcher <{:s}>'.format(self.name)
AttributeError: 'Hatcher' object has no attribute 'name'

Looking at the code, this is due to it missing a str() method like the rest of the example hatcher classes have.