Hi,

I've noticed some minor problems in Tkinter.Scrollbar that would be good
to be addressed. The activate method never returns a value and it also
doesn't accept to be called without an element -- which is accepted by
tcl. When an element is not especified, the current active element
should be returned. It's signature is also a bit strange, I don't see
why it has a parameter named "index" while it never takes an index but
an element.

The second problem is about the set method. It accepts any amount of
arguments, but it only needs to accept two. Passing a tuple in the form
of (number, number) to it isn't accepted, so I don't see much reason to
continue with an *args there.

A tiny patch, can someone take a look with a view to committing, thanks.