Deck Implementation

Implemented a Deck type that has a new function that returns an
unshuffled deck. Also wrote an integration test for the new function to
make sure that it works.

Reviewed-on: #11

src/lib.rs

@@ -2,6 +2,9 @@ use std::error::Error;
 
 mod card;
 mod deck;
+
+pub use deck::Deck;
+
 mod gamestate;
 mod hand;