use make file and requirements file for travis

fix

Author: robfrawley

.travis.yml

@@ -6,9 +6,9 @@ sudo: false
 cache:
   directories: [$HOME/.cache/pip]
 
-install: pip install sphinx~=1.3.0 git+https://github.com/fabpot/sphinx-php.git
+install: pip install -r _build/.requirements.txt sphinx==1.3.0
 
-script: sphinx-build -nW -c _build/ -b html -d _build/doctrees . _build/html
+script: SPHINXOPTS="-nW" make -eC _build html
 
 branches:
   except: