Updated travis.yml to allow build_sphinx command
Commented out much of the travis build temporarily for testing
added code to allow returning the warnings count from build_sphinx
add "-w" to build_sphinx call in travis
Reordered warnings-returncode option to make it less prominent
Updated travis.yml to use correct shell scripts and do the sphinx pre-install
fixed travis.yml to properly match build_sphinx even if it has options
changed failure retcode to just be 1
adjust .travis.yml to remove commented-out portion
added graphviz and latex
switched to texlive-latex-extra
added dvipng to apt-get for sphinx build
Fix .travis.yml with case-specific dependency installs
Merge pull request #713 from eteq/travis-build-docs

Add doc build to travis