New chat view using gtkwebkit

This changes the text buffer widget to a WebKitWebView so that we can
use web technologies to control the display.

This change comes with a new dependency: libwebkit2gtk-4.0. Should
this dependency not be available on the system, we can also build the
client using libwebkit2gtk-3.0. However, the links won't be clickable.

New features:
 - Implemented delivery reports.
 - Avatars are now displayed in the chat window.
 - Links in the chat window are now clickable.

When the client is launched with the -d option, you may right click on
the chat view to open up the dev tools.

In order to improve performance, one WebKitWebView is re-used for all
of the ChatViews, since we only display one at a time.

Tuleap: #1073
Change-Id: Ic945fa6c92f92e391f0362310ddc2f0fa16641bf
[stepan.salenikovich@savoirfairelinux.com: added change_view(); start
 loading webkit on window init; destroy webkit on dispose; prevent
 warning when dispose is called more than once on ChatView]
Signed-off-by: Stepan Salenikovich <stepan.salenikovich@savoirfairelinux.com>
diff --git a/web/web.gresource.xml b/web/web.gresource.xml
new file mode 100644
index 0000000..33ab294
--- /dev/null
+++ b/web/web.gresource.xml
@@ -0,0 +1,14 @@
+  <?xml version="1.0" encoding="UTF-8"?>
+  <gresources>
+    <gresource prefix="/cx/ring/RingGnome">
+      <!-- HTML -->
+      <file>chatview.html</file>
+
+      <!-- JavaScript -->
+      <file>jquery.js</file>
+      <file>linkify.js</file>
+      <file>linkify-string.js</file>
+      <file>linkify-html.js</file>
+      <file>linkify-jquery.js</file>
+    </gresource>
+  </gresources>