v0.7.0 — four stretches, and the typical block

The route of a block now has four stretches, each with its own lever: the
block reaching your peer, the hop into your node, Core building the next
template, and your pool turning it into a job. Where the time goes is where
you can make it shorter.

Beside this block's route there is the typical block: every stop at its
median over the last hundred blocks. One block scatters; the median shows
whether a change made anything shorter. Switch between the two above the
route — the choice is remembered.

The template stop needs Bitcoin Lab 1.22.0. With an older Bitcoin Lab the card
is as it was.