lib: Upgrade Dojo and Dijit from 1.8.3 to 1.12.1

The itemNode and expandoNode elements have changed from img to
span (https://bugs.dojotoolkit.org/ticket/16699), so we now put our
tree icons inside them rather than replacing them.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

lib/dijit/README.md

@@ -0,0 +1,32 @@
+# dijit
+
+**dijit** is the package that contains the widget library for Dojo Toolkit.  It requires the [core][] of the Dojo
+Toolkit and provides a framework for building additional widgets as well as a full set of rich user interface widgets
+including form, layout and data-aware items.
+
+## Installing
+
+Installation instructions are available at [dojotoolkit.org/download][download].
+
+## Getting Started
+
+If you are starting out with Dojo and Dijit, the following resources are available to you:
+
+* [Tutorials][]
+* [Reference Guide][]
+* [API Documentation][]
+* [Community Forum][]
+
+## License and Copyright
+
+The Dojo Toolkit (including this package) is dual licensed under BSD 3-Clause and AFL.  For more information on the
+license please see the [License Information][].  The Dojo Toolkit is Copyright (c) 2005-2016, The JS Foundation.  All
+rights reserved.
+
+[core]: https://github.com/dojo/dojo
+[download]: http://dojotoolkit.org/download/
+[Tutorials]: http://dojotoolkit.org/documentation/
+[Reference Guide]: http://dojotoolkit.org/reference-guide/
+[API Documentation]: http://dojotoolkit.org/api/
+[Community Forum]: http://dojotoolkit.org/community/
+[License Information]: http://dojotoolkit.org/license