[PATCH] Allow CMake to build Sphinx documentation

[Dan Liew]

> Maybe it's because of the :program: tag?

I think it's actually the docs/conf.py configuration file that
populates the man_pages [1] variable based on the contents of
docs/CommandGuide directory

The program:: directive seems to tell sphinx that following option::
directives refer to that tool [2]

[1] http://sphinx-doc.org/config.html#confval-man_pages
[2] http://sphinx-doc.org/domains.html#directive-program

-- 
Dan Liew
PhD Student - Imperial College London