Add music stream notifications

indra/newview/CMakeLists.txt

indra/newview/alpanelstreaminfo.cpp

indra/newview/alpanelstreaminfo.h

indra/newview/alstreaminfo.cpp

indra/newview/alstreaminfo.h

indra/newview/app_settings/settings_alchemy.xml

indra/newview/llappviewer.cpp

indra/newview/llstartup.cpp

indra/newview/lltoastpanel.cpp

indra/newview/skins/default/textures/icons/MusicNote.png

indra/newview/skins/default/textures/textures.xml

indra/newview/skins/default/xui/en/notifications.xml

indra/newview/skins/default/xui/en/panel_music_ticker.xml

.../newview/skins/default/xui/en/panel_stream_info_toast.xml

indra/newview/skins/default/xui/en/strings.xml