test docs via travis

* move build environment into tox
* add new environment installing sphinx and testing for doc errors
* reorganize dependency installs for easier management

tox.ini

@@ -1,11 +1,28 @@
-# This tests the unified codebase (py27, py33) of Pelican.
-# depends on some external libraries that aren't released yet.
-
 [tox]
-envlist = py27,py33,py34
+envlist = py27,py33,py34,docs
 
 [testenv]
-commands =
-    python -m unittest discover
+basepython =
+    py27: python2.7
+    py33: python3.3
+    py34: python3.4
+usedevelop=True
 deps =
     -rdev_requirements.txt
+    nose
+    nose-cov
+    coveralls
+
+commands =
+    {envpython} --version
+    nosetests -sv --with-coverage --cover-package=pelican pelican
+    coveralls
+
+[testenv:docs]
+basepython = python2.7
+deps =
+    sphinx
+    sphinx_rtd_theme
+changedir = docs
+commands =
+    sphinx-build -W -b html -d {envtmpdir}/doctrees . {envtmpdir}/html