Please add data sanitizing

Hello,

I have downloaded your plugin to test it, it works perfectly in WordPress 4.7.2.
I have noticed that you’re not sanitizing the user-entered search parameter $s though and would recommend that you add this in the next update as a security fix.

intval($s) for integers and sanitize_text_field($s) would be sufficient.

For your reference: https://developer.www.ads-software.com/plugins/security/securing-input/

Best regards