fix typo in tutorial doc
Merge pull request #77 from acoffman/master

Change "hear" to "here" in tutorial doc
Show all tracks when artist is selected

- If the artist is selected, all tracks are shown with headers indicating
the albums.
- There is an option called auto_expand_albums. If it's set to false, the
player doesn't automatically select the album when commands such as
win-sel-current are executed and instead selects the artist. If the
albums of this artist are already expanded, the album is selected.