Update TRAVIS sphinx version for Python 3.3

.travis/travis_install.sh

@@ -10,5 +10,5 @@ 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=1.5.1 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=1.5.1 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