Added CSS class .no-js in body_class

I find it helpful to add a CSS class .no-js to the body tag and remove it with 

jQuery(document).ready(function($){ 
  $('body').removeClass('no-js');
}

in the footer (which should be added to footer.php in case you merge this pull request) if the viewer has turned on JavaScript.

This allows better Graceful Degradation of JavaScript/jQuery functions while it doesn't harm performance nor legibility of the code.