leongersen/noUiSlider — pull request #208 by jsDotCr (2014-03-06 16:48:54+00:00)
Title: IE10&11 w/ ZeptoJS 1.1.3 return false instead of null or undefined

I've just casted `disabled` to boolean instead of adding `disabled === false` since they all are falsy values.

Tested on IE9-10-11, Win7 and Win8.1.