Merge unstable into master

This is a placeholder MR to track the differences between 'unstable' and 'master'.

All large features of v1.4.0 should be merged into unstable so that code can be merged and iterated on without impacting master. Additionally any smaller features that tie into the larger features already merged should be merged with unstable.

To help managed the effort of rebasing unstable onto master, developers should rebase unstable onto master every time one of their MRs with unstable is approved.