/*
* Get web-based MusicBrainz CD-ROM submission URL for CD-ROM device associated with this MusicBrainz::Client object.
*
* Use MusicBrainz::Client#device to set the CD-ROM device. Returns nil
* on error.
*
* Aliases:
* MusicBrainz::Client#get_url
* MusicBrainz::Client#get_web_submit_url
*
* Examples:
* url = mb.url
* url = mb.get_url
* url = mb.get_web_submit_url
*
*/
static VALUE mb_client_url(VALUE self) {