Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-includes/js/tinymce/plugins/hr/plugin.js

@@ -0,0 +1,39 @@
+(function () {
+var hr = (function () {
+    'use strict';
+
+    var global = tinymce.util.Tools.resolve('tinymce.PluginManager');
+
+    var register = function (editor) {
+      editor.addCommand('InsertHorizontalRule', function () {
+        editor.execCommand('mceInsertContent', false, '<hr />');
+      });
+    };
+    var Commands = { register: register };
+
+    var register$1 = function (editor) {
+      editor.addButton('hr', {
+        icon: 'hr',
+        tooltip: 'Horizontal line',
+        cmd: 'InsertHorizontalRule'
+      });
+      editor.addMenuItem('hr', {
+        icon: 'hr',
+        text: 'Horizontal line',
+        cmd: 'InsertHorizontalRule',
+        context: 'insert'
+      });
+    };
+    var Buttons = { register: register$1 };
+
+    global.add('hr', function (editor) {
+      Commands.register(editor);
+      Buttons.register(editor);
+    });
+    function Plugin () {
+    }
+
+    return Plugin;
+
+}());
+})();