Add glyphicons fonts in woff2

docs/_includes/getting-started/whats-included.html

@@ -28,7 +28,8 @@ bootstrap/
     ├── glyphicons-halflings-regular.eot
     ├── glyphicons-halflings-regular.svg
     ├── glyphicons-halflings-regular.ttf
-    └── glyphicons-halflings-regular.woff
+    ├── glyphicons-halflings-regular.woff
+    └── glyphicons-halflings-regular.woff2
 {% endhighlight %}
 <!-- NOTE: This info is intentionally duplicated in the README.
 Copy any changes made here over to the README too. -->

less/glyphicons.less

@@ -12,6 +12,7 @@
   font-family: 'Glyphicons Halflings';
   src: url('@{icon-font-path}@{icon-font-name}.eot');
   src: url('@{icon-font-path}@{icon-font-name}.eot?#iefix') format('embedded-opentype'),
+       url('@{icon-font-path}@{icon-font-name}.woff2') format('woff2'),
        url('@{icon-font-path}@{icon-font-name}.woff') format('woff'),
        url('@{icon-font-path}@{icon-font-name}.ttf') format('truetype'),
        url('@{icon-font-path}@{icon-font-name}.svg#@{icon-font-svg-id}') format('svg');