MAINT: Update mock and pull in all the packages it requires

etc/requirements_dev.txt

@@ -3,7 +3,17 @@ nose==1.3.7
 nose-parameterized==0.5.0
 nose-ignore-docstring==0.2
 -e git://github.com/python-excel/xlrd.git@b9239bf2bfc42e088dd2a75c22164757cca9cc4f#egg=xlrd-master
-mock==1.0.1
+
+# These are required my mock or its dependencies
+alabaster==0.7.6
+babel==1.3
+docutils==0.12
+snowballstemmer==1.2.0
+sphinx-rtd-theme==0.1.8
+sphinx==1.3.1
+pbr==1.2.0
+
+mock==1.1.1
 
 # Linting