implement support for sub-processes

[nitram509]

see also #23

[lastchiliarch]

I'm interested in this feature, what kind of subprocess do we want to support?

What about the embedded-subprocesses?

[nitram509]

I did send a message in issue #23 to the requester and hope to get some answer, which could guide us.
From my perspective, I have no strong preference and no strong priority on supporting sub-process.
This means I would consider reviewing a potential PR but also would consider queuing a merge after getting milestone 0.3.0 release (see this issue label for v0.4.0 milestone)

[mintzhao]

So, as for now, sub processes supported?

[jinjaghost]

not yet