使用 CodeIgniter 完成了 Overview、Login 页面。
完善了导航条，将要添加诊断页面。
Merge branch 'master' of https://github.com/raychow/WebCarDiagnostic

Conflicts:
	ci/application/views/footer.php
	ci/application/views/navbar.php
	ci/application/views/overview.php
	css/style.css