This is Bootstrap Flex Slider plugin. Its used for Bootstrap v3.3.7x Themes. Its have admin controls options, Navigation and Directions options in admin panel. Now its also works not bootstrap themes
1. Install Plugin
2. Add slider and use short code [display_flexslider id="SLIDER ID"]
Which version bootstrap theme required for this plugin?
Bootstrap 3.3.7 or later
Its required any JS or CSS file?
No, Not needed. Its working on Bootstrap default JS and Css
http://getbootstrap.com/javascript/#carousel