Increased latest version to 2.1.6b0 [skip ci]

README.rst

 .. vim: set fileencoding=utf-8 :
 .. Thu 18 Aug 12:03:52 CEST 2016
 
-.. image:: http://img.shields.io/badge/docs-v2.1.5-yellow.svg
-   :target: https://www.idiap.ch/software/bob/docs/bob/bob.db.iris/v2.1.5/index.html
+.. image:: http://img.shields.io/badge/docs-stable-yellow.svg
+   :target: https://www.idiap.ch/software/bob/docs/bob/bob.db.iris/stable/index.html
 .. image:: http://img.shields.io/badge/docs-latest-orange.svg
    :target: https://www.idiap.ch/software/bob/docs/bob/bob.db.iris/master/index.html
-.. image:: https://gitlab.idiap.ch/bob/bob.db.iris/badges/v2.1.5/build.svg
-   :target: https://gitlab.idiap.ch/bob/bob.db.iris/commits/v2.1.5
-.. image:: https://gitlab.idiap.ch/bob/bob.db.iris/badges/v2.1.5/coverage.svg
-   :target: https://gitlab.idiap.ch/bob/bob.db.iris/commits/v2.1.5
+.. image:: https://gitlab.idiap.ch/bob/bob.db.iris/badges/master/build.svg
+   :target: https://gitlab.idiap.ch/bob/bob.db.iris/commits/master
+.. image:: https://gitlab.idiap.ch/bob/bob.db.iris/badges/master/coverage.svg
+   :target: https://gitlab.idiap.ch/bob/bob.db.iris/commits/master
 .. image:: https://img.shields.io/badge/gitlab-project-0000c0.svg
    :target: https://gitlab.idiap.ch/bob/bob.db.iris
 .. image:: http://img.shields.io/pypi/v/bob.db.iris.svg

version.txt

-2.1.5
+2.1.6b0
\ No newline at end of file