add Observer and Command

pomelovsd/ExitMaze/Observer|Command/MoveCommand.py

@@ -0,0 +1,15 @@
+from Command import Command
+
+class MoveCommand(Command):
+    
+    def __init__(self, player, target):
+        self.player = player
+        self.target = target
+        self.previous = None
+
+    def execute(self):
+        self.previous = self.player.current
+        self.player.current = self.target
+
+    def undo(self):
+        self.player.current = self.previous