[css-exclusions-1] Add Changes section

Author: xfq

css-exclusions-1/Overview.bs

@@ -856,3 +856,25 @@ Acknowledgments</h2>
   Eugene Veselov,
   Stephen Zilles
   and the CSS Working Group members.
+
+<h2 class="no-num" id="changes">Changes</h2>
+
+  <h3 class="no-num" id="recent-changes">
+  Changes from the <a href="https://www.w3.org/TR/2015/WD-css3-exclusions-20150115/">15 January 2015 Working Draft</a></h3>
+
+  <h3 class="no-num" id="changes-2013">
+  Changes from the <a href="https://www.w3.org/TR/2013/WD-css3-exclusions-20130528/">28 May 2013 Working Draft</a></h3>
+
+  <ul>
+    <li>Editorial fixes.
+  </ul>
+
+  <h3 class="no-num" id="changes-2012">
+  Changes from the <a href="https://www.w3.org/TR/2012/WD-css3-exclusions-20120503/">3 May 2012 Working Draft</a></h3>
+
+  <ul>
+    <li>Split Exclusions from Shapes.
+    <li>Improved exclusion order example.
+    <li>Editorial and markup fixes.
+    <li>See also the Changes section of <a href="https://www.w3.org/TR/css-shapes/#20120503">CSS Shapes</a>.
+  </ul>