gui/html: Various improvements, including embedded context menu

+ update of jQuery
+ adding jQueryUI extension (not really used yet)
+ adding jQueryContext menu extension
+ displaying file icon based on file extension

Change-Id: Ie9cac5d69c751e010f61c64bbe3734890da0aa2f
diff --git a/gui/html/images/README b/gui/html/images/README
new file mode 100644
index 0000000..896d3ff
--- /dev/null
+++ b/gui/html/images/README
@@ -0,0 +1,20 @@
+http://www.splitbrain.org/projects/file_icons
+
+Released to the Public Domain
+Free to use. Provided as is. No warranties.
+
+Note: The big majority of icons where created by the creators listed
+      below. Only a few ones where found on the net. They were too
+      widespread to determine the original author and thus were
+      considered public domain.
+      If you are the author of one of those icons just send a short
+      mail to either be included in the list below or have the icon
+      removed from the package.
+
+Creators:
+
+  Andreas Gohr <andi@splitbrain.org>
+  Michael Klier <chi@chimeric.de>
+  Andreas Barton <andreas.barton@web.de>
+  Hubert Chathi <hubert@uhoreg.ca>
+  Johan Koehne <johankohne@gmail.com>