starting new server
  - create_new_collection_for_source("server nickname", client_URL)
  - probably some short-cut maps like, e.g., "palette name" -> Blender node obj


messaging, use-cases:

init:

C: - sends hello-no-feedback-please message where it states its client_nickname
S: - wants now to create a "(display) server level collection (SLC)" for this client
   - pretends client_URL is "no_feedback"
   - finds SLC that matches in client_nickname and client_URL
     - not found -> create a new one
   - does not reply anything

C: - sends hello message where it states its client_nickname and client_URL
S: - wants now to create a "(display) server level collection (SLC)" for this client
   - finds SLC that matches in client_nickname and client_URL
     - not found -> create a new one
   - replies with "ready" (to test the backward connection)

(maybe also hello-no-reply-please message where it states its client_nickname and client_URL??)



before every batch of data:

C: - should send own colour palette
     - the palette is a list of [name,r,g,b]
       (the name can reflect a function that is represented with that color)
     - list is understood as 0-based indexed array
     - referring to a color is to tell its array index
   - sends client_nickname, palette_name, [...definitions... ]
S: - finds SLC matching the client_nickname, or creates "no_feedback" one
   - finds color node of this palette_name
     - found -> replace its colors (must never delete!!)
     - not found -> create a new one with the given colors


C: - starts by declaring a bucket to be writing into the upcoming graphics
     without a palette_name in which case the specification follows as
     if sending with palette_name = "Default color palette"
     (NB: the "Default color palette" is always present at the server)
|
C: - starts by declaring a bucket to be writing into the upcoming graphics
     and a palette_name to be used for it
   - sends client_nickname, bucket_name and display_time
   - bucket_name should be rather short!
S: - finds SLC matching the client_nickname, or creates "no_feedback" one
   - wants now to create "active" bucket
   - finds bucket that matches in bucket_name and display_time
     - not found -> create a new one
   - finds color node that matches in palette_name
     - not found -> consider the node with "Default color palette"
   - "activates" this bucket_name and this palette_name


- all subsequent display requests from this client
  will appear in its "active" bucket using the "active" palette