Fix for multisite installations, wordpress 3.9.1

The tinymce editor plugin is not loaded in multisite installations, when the main php file is in the mu-plugins folder.

This fixed it here, in vipers-video-quicktags.php:

// Load the custom TinyMCE plugin
	function mce_external_plugins( $plugins ) {
		$plugins['vipersvideoquicktags'] = add_query_arg( 'ver', $this->version, plugins_url( 'vipers-video-quicktags/resources/tinymce3/editor_plugin.js') );
		return $plugins;
	}

https://wordpress.org/plugins/vipers-video-quicktags/