Rewrite the tarot app
Simplifications:
- Get rid of the History class;
- Get rid of the DBus server;
- Get rid of all DBus;
- Get rid of the "retry" parameters for operations that may fail;
- Get rid of the "solo" command-line interface;
- Get rid of the operations on command-line (--new-game, and such);
- Define the use cases;
- Make a bash-like shell;
- Extend the shell with a JSON (resp. whatever) syntax for input/output;
- Use popen to communicate between the GUI and the program with json (resp. whatever) messages.