Fix somme RST errors in README.rst. Add a test in tox.ini to detect such errors

tox.ini

@@ -1,6 +1,7 @@
 [tox]
 envlist=
     flake8,
+    check_rst,
     py27-django17,
     py27-django18,
     py27-django19,
@@ -60,6 +61,13 @@ basepython=python
 deps=flake8
 commands=flake8 {toxinidir}/cas_server
 
+[testenv:check_rst]
+basepython=python
+deps=
+    docutils
+    Pygments
+commands=python {toxinidir}/setup.py check --restructuredtext --stric
+
 [testenv:coverage]
 basepython=python
 passenv=CODACY_PROJECT_TOKEN