Downgrade sphinx to 1.5.1

It seems there is no version `1.5.3` in conda channel. Version prior to `1.5.4` is `1.5.1`: ``` $ conda search sphinx Fetching package metadata ............. sphinx 1.1.3 py26_1 defaults 1.1.3 py27_1 defaults 1.1.3 py27_2 defaults 1.1.3 py33_2 defaults 1.1.3 py26_2 defaults 1.1.3 py27_3 defaults 1.1.3 py33_3 defaults 1.1.3 py26_3 defaults 1.1.3 py33_4 defaults 1.1.3 py26_4 defaults 1.1.3 py27_4 defaults 1.2 py26_0 defaults 1.2 py27_0 defaults 1.2 py33_0 defaults 1.2.1 py33_0 defaults 1.2.1 py27_0 defaults 1.2.1 py26_0 defaults 1.2.2 py34_0 defaults 1.2.2 py26_0 defaults 1.2.2 py27_0 defaults 1.2.2 py33_0 defaults 1.2.2 py34_1 defaults 1.2.2 py33_1 defaults 1.2.2 py27_1 defaults 1.2.2 py26_1 defaults 1.2.2 py34_2 defaults 1.2.2 py26_2 defaults 1.2.2 py33_2 defaults 1.2.2 py27_2 defaults 1.2.3 py26_0 defaults 1.2.3 py34_0 defaults 1.2.3 py33_0 defaults 1.2.3 py27_0 defaults 1.3.1 py35_0 defaults 1.3.1 py26_0 defaults 1.3.1 py27_0 defaults 1.3.1 py33_0 defaults 1.3.1 py34_0 defaults 1.3.5 py34_0 defaults 1.3.5 py27_0 defaults 1.3.5 py35_0 defaults 1.4.1 py34_0 defaults 1.4.1 py27_0 defaults 1.4.1 py35_0 defaults 1.4.6 py34_0 defaults 1.4.6 py27_0 defaults 1.4.6 py35_0 defaults 1.4.8 py35_0 defaults 1.4.8 py34_0 defaults 1.4.8 py27_0 defaults 1.5 py35_0 defaults 1.5 py34_0 defaults 1.5 py27_0 defaults 1.5.1 py35_0 defaults 1.5.1 py36_0 defaults 1.5.1 py34_0 defaults * 1.5.1 py27_0 defaults 1.5.4 py35_0 defaults 1.5.4 py27_0 defaults 1.5.4 py36_0 defaults ```

Downgrade sphinx to 1.5.1
33bb44c8 · notoraptor · GitHub · e2357e16 · 33bb44c8
--- a/.travis/travis_install.sh
+++ b/.travis/travis_install.sh
@@ -9,6 +9,6 @@ else
 fi
 source activate pyenv
-if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then conda install --yes -q mkl numpy=1.9.1 scipy=0.14.0 nose=1.3.0 pip flake8=2.3 six=1.9.0 pep8=1.6.2 pyflakes=0.8.1 sphinx=1.5.3 mkl-service libgfortran=1; fi
+if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then conda install --yes -q mkl numpy=1.9.1 scipy=0.14.0 nose=1.3.0 pip flake8=2.3 six=1.9.0 pep8=1.6.2 pyflakes=0.8.1 sphinx=1.5.1 mkl-service libgfortran=1; fi
-if [[ $TRAVIS_PYTHON_VERSION == '3.3' ]]; then conda install --yes -q mkl numpy=1.9.1 scipy=0.14.0 nose=1.3.4 pip flake8=2.3 six=1.9.0 pep8=1.6.2 pyflakes=0.8.1 sphinx=1.5.3 mkl-service; fi
+if [[ $TRAVIS_PYTHON_VERSION == '3.3' ]]; then conda install --yes -q mkl numpy=1.9.1 scipy=0.14.0 nose=1.3.4 pip flake8=2.3 six=1.9.0 pep8=1.6.2 pyflakes=0.8.1 sphinx=1.5.1 mkl-service; fi
 source deactivate