Fix return to root after selecting items from playlist viewer

When selecting an item, Rockbox only checked that
playback was stopped before entering the viewer and
went to the WPS if music had started playing afterwards,
but returned to the root menu otherwise

The WPS will now be displayed whenever a new item has been
selected, even if audio was paused or playing before.

boomark_autoload required slight adjustments to its return values,
so that the WPS would not be opened after a user cancels out of
the bookmark selection screen for a playlist, since it  previously
returned true in that case, too.

Change-Id: I231ea788e2f80fdda5fe4ad4d2420450931f686f

apps/playlist_catalog.h

@@ -29,7 +29,7 @@ void catalog_set_directory(const char* directory);
 
 /* 
  * View list of playlists in catalog.
- *  ret : true if no error
+ *  ret : true if item was selected
  */
 bool catalog_view_playlists(void);