open-source-silicon.dev

#138 Sphinx + ReadTheDocs (develop)
Pull request opened by wgryncewicz
This PR introduces Sphinx and ReadTheDocs setup for current markdown documentation.  
It it a clean re-submit of <https://github.com/efabless/openlane/pull/134|#134> for `develop` branch

Preview is available here:  
<https://openlane-docs.readthedocs.io/en/rtd-develop/|https://openlane-docs.readthedocs.io/en/rtd-develop/>
<https://github.com/efabless/openlane|efabless/openlane>
Travis CI: Build Created