snippets/python-mode/super: New file

This snippet expands a super() call inside a Python method with correct
class, object, and method parameters.

E.g.:

```Python
class Foo(object):
    def __init__(self, bar):
        super_|_

=>

class Foo(object):
    def __init__(self, bar):
        super(Foo, self).__init__(_|_)
```