session and procedure states are separated

sessionManager.go

 	openID string //who is this?
 	count  int    //  number of message in the Queue, channel
 	jobs   chan InWechatMsg
-	data   openIDSessionData //session data, that needs to be saved to disk
+	data   openIDSessionData    //session data, that needs to be saved to disk
+	states map[string]chatState //map from procedure to its current states
 }
 
 type workDone struct {