Slide callback and change event not firing

Added extra function call of 'call' within the 'val' function, to
trigger the 'slide' event, once slider's value is changed
programmatically.

Note: I wasn't been able to find a better reference to 'noUi-target', within that function scope. So if you feel like there's a better way, feel free to comment.

P.S. You should totally switch to spaces instead of tabs ;)