Added automatic close of Brackets.

IPython/html/static/notebook/js/codecell.js

@@ -101,7 +101,8 b' var IPython = (function (IPython) {'
             },
             mode: 'ipython',
             theme: 'ipython',
-            matchBrackets: true
+            matchBrackets: true,
+            autoCloseBrackets: true
         }
     };