branch wip-actors created (now 0346ac2)

[Ludovic Courtès]

civodul pushed a change to branch wip-actors.

      at 0346ac2  base: Add comment giving an overview of the actors.

This branch includes the following new commits:

     new 9b227ab  http: Correctly render build products as JSON.
     new 8fa6bcf  base: Split jobset evaluation into several actors.
     new e4233a9  config: Define '%runstatedir'.
     new d279494  register: Listen for commands on a "bridge" socket.
     new 7d86c51  http: Send jobset registration requests to the bridge.
     new 84e2a63  utils: Add 'get-message*'.
     new c2ac72d  http: Add /jobset/SPEC/hook/evaluate route to trigger a 
jobset.
     new 7fdd780  base: Move evaluations to a separate actor.
     new 0ddd43f  base: Implement ‘update-jobset’.
     new f664516  http: /admin/specification/edit notifies jobset via the 
bridge.
     new b9f7f6e  base: Add pages for structure.
     new b0f9355  Move store and GC helpers from (cuirass base) to (cuirass 
store).
     new 56902e7  base: Define new “builder” actor with two implementations.
     new 0346ac2  base: Add comment giving an overview of the actors.