[Twisted-Python] Deferred documentation rewrite

[ezyang]

Excerpts from Jamu Kakar's message of Thu Jul 30 15:03:16 -0400 2009:
> Your outline looks nice.  Something that *really* helped me a lot
> with Deferreds was seeing how they are modelled after standard
> Python flow control behaviour.  I guess that's what the first
> section your proposing is about.

Right.  Everything you could do synchronously, you can do
asynchronously (and a bit more too).  It just /looks/ really
weird.

> Jono Lange gave a presentation recently (can't remember what it was
> called... maybe something about being an evil hacker or about how
> your code sucks and he hates you) where he presented step-by-step
> slides that shows some normal Python code and then the asynchronous
> Deferred-using equivalent.  Even though I understood the principles
> reasonably well before attending his talk, the way he presented them
> in his slides was very effective and helped me clarify that
> understanding.  If he's willing, which I suspect he will be, I
> recommend you look at the slides and steal his good ideas. :)

That would be very helpful!

Cheers,
Edward