Allow external access to override plugin filters

No problem here, just wanted to share a modification that I made to the plugin to make it more malleable and serve my purposes better.

Line 17

self::$_this = $this;

Line 37

static function this() {
	return self::$_this;
}

This allowed me to remove filters. For example:

if(class_exists('default_featured_image')) {
	$default_featured_image_instance = default_featured_image::this();
	remove_filter( 'get_post_metadata', array( $default_featured_image_instance, 'set_dfi_meta_key'));
}

http://wordpress.org/plugins/default-featured-image/