Timed execution in eval

[castironpi at gmail.com]

> >  > and I want to be able to stop [functions] if they run too long.
>
> > That's tricky [due to a synthetic limitation].

It would suck if you couldn't hold the GIL for as long as you need
to.  But how much is it used?

Wrote the docs:
> when two threads simultaneously increment the reference count of the same object

Well, the example sucked.  Just synchronize ref count manipulation.
Every OS has locking primitives, and a library exists to deny requests
to block that lock dead.  How integral is the GIL to Python?

> The Python interpreter is not fully thread safe

-Make- it so.