docs: travis-sphinx can't be used for building
docs: travis-sphinx can't be used for building

Our Makefile handles cloning and testing release and development
versions of cclib, which travis-sphinx cannot do.

ATenderholt/cclib,berquist/cclib,langner/cclib,berquist/cclib,cclib/cclib,berquist/cclib,cclib/cclib,ATenderholt/cclib,langner/cclib,cclib/cclib,langner/cclib