Add README and default to TicTacToe

README.md

+This repository is a rust simple board game engine used as a live
+coding support for an rust introduction seminar
+
+To build and test it
+
+```
+cargo test
+cargo run
+```
+
+

src/main.rs

@@ -44,8 +44,8 @@ where
 }
 
 fn main() {
-    //let board = TicTacToe::new();
-    let board = board::coin_flip::FlipCoin::new(42);
+    let board = TicTacToe::new();
+    //let board = board::coin_flip::FlipCoin::new(42);
     play(board);
 }