Added the list command.
Added the list command.

This command will let you search the database for metadata. For example, if you
just wanted all the artists in your database, you can use `list artist`. If you
wanted to find all albums that the band "name" owns, you would use:
`list album artist "name"`.

You could search for `artist`, `album`, `title`, `track`, `name`, `genre`,
`date`, `composer`, `performer`, `comment`, or `disc`.

For more info, see: http://mpd.wikia.com/wiki/MusicPlayerDaemonCommands#list.

fhs/gompd