sound applet: linuxmint/Cinnamon#2170 instead of hardcoding the default theme, Gtk search pathes are used instead to use the icons in the current theme, for icons player-*
sound applet: linuxmint/Cinnamon#2170 instead of using theme defined icons, symbolics media-playback-* are used
sound applet: fixed variant number two, TextImageMenuItem had an argument too much
Merge pull request #3593 from pixunil/sound-applet-theme-issue

Fixed #2170: sound applet player status icons