query_player: re-prompt until a legal move is entered (#1332)

Loop query_player until the entered move is legal. Supersedes #1078 by @SandersLin.

Author: dmeoli

games.py

@@ -183,11 +183,15 @@ def query_player(game, state):
     print("")
     move = None
     if game.actions(state):
-        move_string = input('Your move? ')
-        try:
-            move = eval(move_string)
-        except NameError:
-            move = move_string
+        while True:
+            move_string = input('Your move? ')
+            try:
+                move = eval(move_string)
+            except NameError:
+                move = move_string
+            if move in game.actions(state):
+                break
+            print('illegal move, try again')
     else:
         print('no legal moves: passing turn to next player')
     return move