Merge branch 'master' of https://github.com/twbs/bootstrap

Conflicts:
	dist/css/bootstrap.css.map

docs/_includes/components/thumbnails.html

@@ -33,7 +33,7 @@
 <div class="row">
   <div class="col-xs-6 col-md-3">
     <a href="#" class="thumbnail">
-      <img data-src="holder.js/100%x180" alt="...">
+      <img src="..." alt="...">
     </a>
   </div>
   ...
@@ -80,7 +80,7 @@
 <div class="row">
   <div class="col-sm-6 col-md-4">
     <div class="thumbnail">
-      <img data-src="holder.js/300x300" alt="...">
+      <img src="..." alt="...">
       <div class="caption">
         <h3>Thumbnail label</h3>
         <p>...</p>