Rename requirements.txt to dev-...txt to clarify that these are NOT core dependencies.

(Installing packaged sphinx should speed up CI builds significantly and pip
should figure out it doesn't need to install it.)

.travis.yml

@@ -2,9 +2,10 @@ language: python
 python:
   - "3.3"
 install:
-  - "pip install -r requirements.txt"
+  - "sudo apt-get install python3-sphinx"
+  - "pip install -r dev-requirements.txt"
 script:
   - "pep8  --ignore E501 i3pystatus tests"
   - "PYTHONPATH=. py.test"       # run unit tests
   - "python setup.py install"    # test install
-  - "sphinx-build -W docs html"     # test building docs
+  - "sphinx-build -W docs html"  # test building docs

dev-requirements.txt

@@ -1,5 +1,5 @@
 pytest>=2.5
-sphinx>=1.2
+sphinx>=1.1
 colour>=0.0.5
 mock>=1.0
 pep8>=1.5