Simplify tooltip

Although usage tips are handy and useful, they look clunky in the tooltip.
They also lack localization and this project doesn't provide translations.

Show artist and song name during playback and "Rhythmbox" the rest of the time.

tray_icon.py

@@ -236,20 +236,16 @@ class TrayIcon(GObject.Object, Peas.Activatable):
         if playing:
             self.icon.set_from_file(self.play_icon)
             current_entry = self.shell.props.shell_player.get_playing_entry()
-            self.set_tooltip_text(current_entry.get_string(RB.RhythmDBPropType.ARTIST) + " - " + current_entry.get_string(RB.RhythmDBPropType.TITLE))
+            self.set_tooltip_text("%s\n%s" % (current_entry.get_string(RB.RhythmDBPropType.ARTIST), current_entry.get_string(RB.RhythmDBPropType.TITLE)))
         else:
             self.icon.set_from_file(self.rhythmbox_icon)
-            self.set_tooltip_text()
+            self.set_tooltip_text("Rhythmbox")
 
     def set_tooltip_text(self, message=""):
         """
         Sets tooltip to given message
         """
-        prepend = ""
+        self.icon.set_tooltip_text(message)
-        if len(message) > 0:
-            prepend = "\r\n"
-        tooltip_text = message + prepend + "(Scroll = volume, click = visibility, middle click = next)"
-        self.icon.set_tooltip_text(tooltip_text)
 
     def do_activate(self):
         """
@@ -271,7 +267,7 @@ class TrayIcon(GObject.Object, Peas.Activatable):
         self.icon.connect("button-press-event", self.toggle_player_visibility)
         self.player.connect("playing-changed", self.on_playing_changed)
 
-        self.set_tooltip_text()
+        self.set_tooltip_text("Rhythmbox")
 
     def on_scroll(self, widget, event):
         """