Magento 2: include css/script files

 <css src="https://use.fontawesome.com/releases/v5.0.8/css/all.css" src_type="url"/>          
         <css src="css/flexslider.css"/>
         <css src="css/custom.css" media="all"/>
        <script src="js/jquery-2.2.2.min.js"/>
        <script src="js/custom.js"/>
<script type="text/javascript" src="<?php echo $this->getViewFileUrl('js/jquery.superslides.js'); ?>"></script>   



<script  type="text/javascript">
    require([
        "jquery"
    ], function($){
            $('#slides').superslides({
                hashchange: false
            });
        });
</script>