Add non-basic usage example.

[adiroiban]

The current basic examples are fine... but it uses a single python mode for both the main process and the AMP workers.

When I started to see how to use ampule I was a bit confused about what is executed in the main reactor and what is executed in the child process.

I have created this example in which there are 2 python modules.
It helped me as an example of what is executed in the child.
It uses the setproctitle module so that at least in Linux, when you run ps you don't see the whole bootstrap code.

https://gist.github.com/adiroiban/d2bb96a52634d7aa07493ac3df2ecfb0

Let me know if you think that this example makes sense and it it worth being included in the repo.

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For my work, I ended up using Python stdlib multiprocess.Pool