Sound Applet: use Math.round instead of .floor on volume values and better mute handling
Sound Applet: play sound "volume" on scroll event of the sliders
Sound Applet: scrollevent on the icon: 0% -> 5% instead of 0% -> 10%
Merge pull request #3630 from pixunil/sound-applet-issue

Fixing sound applet issues #2807 and #3284