Update applet.js

- add custom launcher
- sliders improvements :
	- add an option to override theme (to correct right margin and keep mark at 100% for 150% slider)
	- for 150% slider : make 100% "magnetic" :
		- on slow dragging
		- on clic close to the mark (between 98% to 102%)
		- on clic beside the slider add step at 100%
		- volume slider support horizontal scroll with 1% step 

- player improvements :
	- support no squarish album cover (specialy landscape cover)
	- add ability to scroll track time with step 1 second
	- add ability to seek track time with left/right arrow key step 10 seconds
	- clic at the right beside the track postionslider go to the end of the track