Boilerplate to get blockdiag doc generated with sphinx

I love sphinx for documentation, it comes from the python world and
comes out with a plugin to integrated blockdiag.com drawings.

Using tox should simply all the run, specially if we want to get the doc
generated automatically via Jenkins.

Change-Id: Ia4f01c46fd667c5fc087b6d84a0478f816489819
Dev and deploy flowchart using blockdiag

Change-Id: Ib0ea554a270259f7cd0e595341aa15868b8a122c