Add basic gitignore to project

These exclusions stop operating specific (and non project related)
files from being added to the repository.
Add generic robots.txt

This file notes which URL paths should not be indexed by search
engines.  These may or may not exist on server used for web hosting.
Update the Readme with a note

Currently, this repository represents a proof of concept and not the
actual site.  One day, it might evolve into that.
Merge pull request #1 from epreston/project-setup

Project Setup