Reduce the requirements for sanity

requirements.txt

@@ -1,27 +1,2 @@
-alabaster==0.7.9
-appdirs==1.4.0
-argh==0.26.2
-Babel==2.3.4
-backports-abc==0.5
-certifi==2017.1.23
-docutils==0.13.1
-imagesize==0.7.1
-Jinja2==2.9.5
-livereload==2.5.1
-MarkupSafe==0.23
-packaging==16.8
-pathtools==0.1.2
-pkg-resources==0.0.0
-port-for==0.3.1
-Pygments==2.2.0
-pyparsing==2.1.10
-pytz==2016.10
-PyYAML==3.12
-requests==2.13.0
-singledispatch==3.4.0.3
-six==1.10.0
-snowballstemmer==1.2.1
-Sphinx==1.5.2
-sphinx-autobuild==0.6.0
-tornado==4.4.2
-watchdog==0.8.3
+sphinx
+sphinx-autobuild