added a get boat count helper method(#2)

src/services/GameState.service.js

@@ -162,6 +162,24 @@ export class GameStateService {
         }
         return(score);
     }
+
+    get_boat_count(){
+        let i = 1;
+        let j = 1;
+        let boat_count = 0;
+        for(i; i<=9; i++)
+        {
+            for(j; j<=9; j++)
+            {
+                let cell = this.player_x_game_board[this.current_opponent][i][j];
+                if(cell.render === GridCellState.Damaged || cell.render === GridCellState.Sunk || cell.render === GridCellState.Ship )
+                {
+                    boat_count++;
+                }
+            }
+        }
+        return(boat_count);
+    }
 }
 
 // Export a single instance, so it can be shared by all files