I’m afraid the plugin does nothing that can affect the editor toolbar. The code only ties into WordPress’ short code system. It does not alter the database in any way that can affect the behavior of WordPress if it’s not installed, nor does it alter any core files. This is why the problem you’re experiencing did not resolve itself when you disabled and uninstalled the plugin. I’m very sorry you’re having difficulties, but this plugin is not the cause of the problem you’re experiencing.
Happily, you don’t have to simply take my word for it. I would encourage you or a developer to examine the code and verify what I’ve said here.
http://plugins.svn.ww.wp.xz.cn/responsive-video-light/tags/1.3.2/responsive-video-light.php
Please let me know if I can help clarify anything that’s happening in the code.
I will be attending to it as soon as I have time. But there was nothing else that happened on the site. I installed the plugin and the editor toolbar disappeared.