deps/jansson: Update jansson to version 2.9

Closes jp9000/obs-studio#797

deps/jansson/README.rst

@@ -2,15 +2,20 @@ Jansson README
 ==============
 
 .. image:: https://travis-ci.org/akheron/jansson.png
-  :alt: Build status
   :target: https://travis-ci.org/akheron/jansson
+  
+.. image:: https://ci.appveyor.com/api/projects/status/lmhkkc4q8cwc65ko
+  :target: https://ci.appveyor.com/project/akheron/jansson
+
+.. image:: https://coveralls.io/repos/akheron/jansson/badge.png?branch=master
+  :target: https://coveralls.io/r/akheron/jansson?branch=master
 
 Jansson_ is a C library for encoding, decoding and manipulating JSON
 data. Its main features and design principles are:
 
 - Simple and intuitive API and data model
 
-- Comprehensive documentation
+- `Comprehensive documentation`_
 
 - No dependencies on other libraries
 
@@ -46,8 +51,7 @@ use autoreconf::
 Documentation
 -------------
 
-Prebuilt HTML documentation is available at
-http://www.digip.org/jansson/doc/.
+Documentation is available at http://jansson.readthedocs.io/en/latest/.
 
 The documentation source is in the ``doc/`` subdirectory. To generate
 HTML documentation, invoke::
@@ -59,5 +63,6 @@ Then, point your browser to ``doc/_build/html/index.html``. Sphinx_
 
 
 .. _Jansson: http://www.digip.org/jansson/
+.. _`Comprehensive documentation`: http://jansson.readthedocs.io/en/latest/
 .. _`MIT license`: http://www.opensource.org/licenses/mit-license.php
 .. _Sphinx: http://sphinx.pocoo.org/