add delete button and different history loading with cache in local pc.
Merge branch 'develop' of https://github.com/m1uan/voc4u_nodejs_webserver into develop

Conflicts:
	api/ctrl/WordsCtrl.js
	assets/css/index.css
	assets/js/controler.js
	engine/words.js
	test/engine/packageTest.js
	test/engine/wordsTest.js
	views/index.jade