add background music with mute button

[JohnRDOrazio]

to add to the immersive experience, sound effects could / should be added. Background music, with sound effects when interactions take place:

• a single country is double clicked and zoomed into
• a placemark is clicked and the info window is opened
• a virtual tour starts
• etc.

At the same time, some users may rather keep the experience silent, so a mute button should be added, at least for the background music... perhaps there could be a preferences area, where a user can choose what to mute: just the background music, or all sound effects.