The Big Switch

And so it begins ...

Merge-in the "next" branch, that contains the new version of LISA. The
old master can be found under the "legacy" branch that has been only
taking minor tweaks for quite a while now, while hot new stuff were
merged into next.

A transition guide listing major API changes and how to port code from
LISA legacy is available here:
https://lisa-linux-integrated-system-analysis.readthedocs.io/en/master/transition_guide.html

note: this is not a merge commit proper, in order to speed up git
subtree split. The commit of "next" branch merged is:
c543fb77 Merge pull request #871 from douglas-raillard-arm/_pr133