Refacto - No jQuery needed

### I'm taking jQuery and its UI friends out of here d:D

Following #27

I'm proposing a version of the slider without jQuery UI.
It's a **HUGE** refactorisation but it's a good practice ;)
I know it is still missing [ton of stuff](http://jqueryui.com/slider/) but it feels good to have it without jQuery.

I need feedback and suggestion to make it cooler.

[Here is a demo of how it's look like](http://douglasduteil.github.io/ui-slider/demo/)
[Here is a README](https://github.com/douglasduteil/ui-slider/blob/refacto-no-jqui/README.md)