Alrighty then!

Since I had also done some work on CallTips.py since the previous patch,
I've worked up a merged version, including stuff from the py3k version
and better tests.

Changes since the first patch:
* add support for callable instances (e.g. __call__)
* use inspect, which does the hackish stuff for us, such as using
<object>.im_func where needed and formatting doc-strings appropriately
* use isinstance instead of type checking, like in the py3k branch
* rename get_arg_text to get_arg_text_and_doc
* add test cases for callable instances, classmethods, staticmethods and
old-style classes
* rework testing code
* tested extensively (only on WinXP, Python2.5)

I'm attaching a patch relative to the current SVN head, and another one
relative to the current SVN head with the previous patch applied.