Allow piping from inputs

[hovsep]

Currently component clear it's inputs before pipes are flushed. It works fine, but adds a significant limitation: it is unable to pipe FROM inputs.

Why do we need to pipe from inputs?

It may be super useful to read inputs, to pass them to another component for read only operations like logging, analytics, monitoring.

I personally found myself creating "bypass" outputs and forwarding signals just to copy them.
It looks like we can flush pipes in smarter ways, so piping from inputs will be available

[hovsep]

Implemented #45