ocarina: Single list attrs

I was recreating this list once for each of playlist, library and queue.
I expect it is easier to manage from a single location.

ocarina/library.py

@@ -13,8 +13,7 @@ def set_label_text():
 	LIB_PAGE.label.set_text("Library (%s)" % library.num_visible())
 
 def fill_library():
-	attrs = ("id", "title", "lenstr", "artist", "album", "year")
-	songs = libsaria.sources.list_library(*attrs)
+	songs = libsaria.sources.list_library(*sources.column.attrs)
 	lib_page.insert(songs)
 	set_label_text()
 fill_library()

ocarina/playlist.py

@@ -13,8 +13,7 @@ def set_label_text():
 	PLAYLIST_PAGE.label.set_text("Playlist (%s)" % playlist.num_visible())
 
 def fill_playlist():
-	attrs = ("id", "title", "lenstr", "artist", "album", "year")
-	songs = libsaria.sources.list_playlist(*attrs)
+	songs = libsaria.sources.list_playlist(*sources.column.attrs)
 	playlist_page.insert(songs)
 	set_label_text()
 fill_playlist()

ocarina/queue.py

@@ -19,8 +19,7 @@ def set_visible():
 		body.show_page(QUEUE_PAGE)
 
 def fill_queue():
-	attrs = ("id", "title", "lenstr", "artist", "album", "year")
-	songs = libsaria.sources.list_queue(*attrs)
+	songs = libsaria.sources.list_queue(*sources.column.attrs)
 	queue_page.insert(songs)
 	set_label_text()
 	set_visible()

ocarina/sources/column.py

@@ -2,6 +2,7 @@
 
 import gtk
 
+attrs     = ("id", "title", "lenstr", "artist", "album", "year")
 columns   = ["Id", "Title", "Length", "Artist", "Album", "Year"]
 col_width = [   2,     300,       60,      125,     125,     50]