see https://en.wikipedia.org/wiki/Alpha_max_plus_beta_min_algorithm

They do not need to know anything about the Camera or any of their screen
position, they just draw themselves around the 0:0 coordinates, and they use
the given sf::RenderStates (which contains the translation to draw the
Sprite at the correct screen position).

And fix a few related things in Tasks and Works

Instead of just RemoteClient

And use it between the master server and the menu client
We still need to use that between the slaves and the master server (with
client certificate verification), but all the work is basically done

fix #2352

Only TCPSocket are available at the moment, but this will be useful to use a
TCPSocket easily

It manages subprocesses, wait for the SIGCHILD, etc

fix #2364

- Master server is now composed of two separate servers, one accepting game
  clients, and one accepting slave servers
- Introduce some way to communicate over IPC (used between the slaves their
  child game servers)
- Child game servers are spawned and managed by the slave

Since each process has only one single io_service object

It is replaced by the attack range. And if we later decide to implement an
acquisition-like feature, it should be in the Vision component

The fs and bs are now expressed as a Duration
We implement non-ranged attacks
And we do not use acquisition anymore

fix #3034