Added IE11 and IE10 support, and modify the dots mode naming.

In previously version if you are using the custom dots mode, you would have to do the following to know if a dot is active or not.

if(slideIndex === currentSlide)

Now you can just do

const CustomDot = ({ active }) => {
   return <li className={active? 'active' : 'not-active'}><button>I am a dot</button></li>
}