title: WooCommerce rename "Free Shipping" field on checkout
body: <p>We have included shipping costs into the cost of the individual products. As such we enabled free shipping, but we want to rename "Free Shipping" text which appears on checkout to say "Shipping Included In Cost of Product" or something similar to that. I don't really know how to create a filter to do this .</p>
  
  <p>I found the verbiage in woocommerce/classes/shipping/free-shipping/class-wc-shipping-free-shipping.php</p>
  
  <p>I also found <a href="http://docs.woothemes.com/document/hooks/" rel="nofollow">http://docs.woothemes.com/document/hooks/</a> but again I don't really know the proper code to create an action / hook to change this text via my functions.php file.</p>
  
  <p>Here is a screen shot to the area of the template I am referring to - <a href="http://cl.ly/image/0i311G3Y163E" rel="nofollow">http://cl.ly/image/0i311G3Y163E</a></p>