Avoid returning object.__init__ docstring with Jython and IronPython.

`inspect.isroutine(object().__init__)` returns True with Jython and
IronPython. Luckily we can easily use `inspect.isfunction(...) or
inspect.ismethod(...)` instead.

Fixes #13.
Fixed support with Python/Jython < 2.5.
Fix handling Ctrl-C (and signals) with Jython and IronPython

Fixes #14. The fix doesn't work with Jython on Windows, though.