Adding Roadmap / TODO in README.md

* Putting plans into shared artifacts helps people get on the same page
* Also some small formatting fixups
Updates to Troubleshooting section of README

* Going through a certs deployment with @stvstnfrd showed us some
  places where our most common set of assumptions (ubuntu, possibly
  running in a VM) may break Python's mostly-posix expectations.

  This gives people ideas where to look when debugging.
README: clarification of LC_ALL use
README: Remove references to specific ops people
Merge pull request #20 from edx/jrbl/README_updates

README: Add Roadmap, update troubleshooting