Do not calculate position on hidden elements

[coderjp]

If an slider is hidden on init, it will always set its min attribute as its value. This overwrites any default value that is set via the value attribute.

This commit will prevent a hidden element from calculating its position and instead rely on the defaults set.

This will also prevent any the onSlide and onSlideEnd callbacks from being run on a hidden element - however if it's hidden, these wouldn't be trigger-able anyway!

[andreruffert]

First of all thanks for your pr maybe I misunderstood you but I don't get your point.
Check this example it works fine for me.
The input[type="range"] is hidden on initialization and sets the correct attributes.

The problem is if you show the hidden element later somehow and don't calculating it's position etc. the UI of the slider is not correct and that's what you probably expect if it was initialized.

[coderjp]

After further testing it only happens when an !important is on the hidden class as can be seen here:
http://codepen.io/anon/pen/YXqbvK

As the website I am using it on uses Bootstrap, hide and hidden both have !important in their classes. It looks like the "display: none !important" is overwriting the rangeslider classes

[boekkooi]

@coderjp Why not use .is(':hidden')

[ge0ffray]

Hello, I just sent a PR correcting this problem : #188