[Development] Allow to do parallel integration (was: Proposal: New branch model)

[Edward Welbourne]

Jedrzej Nowacki (30 January 2019 11:08)
> Mårten pointed out that we can check for conflicts up front. Not only against
> HEAD of the target branch, but also against all build branches. That is even
> nicer as there is no need to start a job that would likely to be rejected at
> the end.

That'll only find VC-level conflicts.
It's no help in finding the kinds of breakage that only testing reveals.
It'll also sometimes lead to rejecting a change needlessly, because the
already-integrating branch it conflicts with is about to fail its testing.
Still, I guess restaging a little later can fix that ...

	Eddy.