Update simpleSlider.js

Added an if statement to line 73 to make the slide indicator clickable only if it's not already active.
I believe this solves the issue where it hides the content when clicking the indicator for the already active slide.
I would imagine that it'd be better to modify the "nextSlide" function, but i couldn't figure out how to do so to keep it from hiding the slide's content. 
if(!($(this).hasClass("active")))
{
	obj.nextSlide($(this).data('index'));
}