add decoration of feedback
	modified:   static/css/task_base.css
	modified:   static/js/fedtask.js
	modified:   templates/fedtask/task_base.html
	modified:   templates/fedtask/task_ui1_test.html
	modified:   templates/fedtask/task_ui1_train.html
	modified:   templates/fedtask/task_ui2_test.html
	modified:   templates/fedtask/task_ui2_train.html