Created Hand Type

Created a Hand type that can also calculate the sum of the cards in the
hand. Also wrote a display for it so that we can just print hands out.

Reviewed-on: #13

src/lib.rs

@@ -1,6 +1,9 @@
 use std::error::Error;
 
 mod card;
+
+pub use card::Card;
+
 mod deck;
 
 pub use deck::Deck;
@@ -8,6 +11,8 @@ pub use deck::Deck;
 mod gamestate;
 mod hand;
 
+pub use hand::Hand;
+
 pub fn run() -> Result<(), Box<dyn Error>> {
     println!("Hello, world!");