Refactor the game flow and support splits

Behaves more like a client/server, rather than just taking a decision
function. The CLI logic is more complex now, but the game is more
flexible and and support splits (basically branching the hand off)

src/lib.rs

@@ -1,3 +1,4 @@
 pub mod card;
+pub mod error;
 pub mod game;
 pub mod hand;