Add docs to sdist.
Add docs to sdist.

When packaging from source we sometimes desire the documentation to be
built for the local system.  This adds the documentation to any future
pypi distributions.

swyytch/supernova,coreypobrien/supernova,roaet/supernova,major/supernova,major/supernova,immanetize/supernova,lmaycotte/supernova,badcure/supernova,coreypobrien/supernova,immanetize/supernova,swyytch/supernova,roaet/supernova,badcure/supernova,lmaycotte/supernova