Use just holder.js instead of docs.min.js in examples when possible

And add explanatory comments to the Carousel & Dashboard examples regarding holder.js

[skip sauce]

docs/examples/carousel/index.html

@@ -208,7 +208,8 @@
     <!-- Placed at the end of the document so the pages load faster -->
     <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
     <script src="../../dist/js/bootstrap.min.js"></script>
-    <script src="../../assets/js/docs.min.js"></script>
+    <!-- Just to make our placeholder images work. Don't actually copy the next line! -->
+    <script src="../../assets/js/vendor/holder.js"></script>
     <!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
     <script src="../../assets/js/ie10-viewport-bug-workaround.js"></script>
   </body>

docs/examples/dashboard/index.html

@@ -240,7 +240,8 @@
     <!-- Placed at the end of the document so the pages load faster -->
     <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
     <script src="../../dist/js/bootstrap.min.js"></script>
-    <script src="../../assets/js/docs.min.js"></script>
+    <!-- Just to make our placeholder images work. Don't actually copy the next line! -->
+    <script src="../../assets/js/vendor/holder.js"></script>
     <!-- IE10 viewport hack for Surface/desktop Windows 8 bug -->
     <script src="../../assets/js/ie10-viewport-bug-workaround.js"></script>
   </body>