splitting node and process

[asmodehn]

It will make things clearer. WIP : #28

[asmodehn]

This way we can have multiple nodes in one process.
It should allow easier scaling (add node in different ways to build a full node network in a process).
We can get inspiration from celery tasks and such systems, but tasks are quite different to nodes...

[asmodehn]

Better solution implemented in #35