Moved config files into 'files' subdir
Added conditional state to clean build dir
Switched building docs to a cmd.wait
Comment out debugging example setting

Sure it's an example file but this helps the copy-and-pasters from
having to comment/modify the setting.
Wrap URI in brackets to avoid ambiguity
Renamed saltdocs formula to sphinxdocs

We're building many docs here not just Salt's docs.
Updated variable names from saltdocs to sphinxdocs
Refactor hardcoded Salt repo data into iterable for many docs
Reformat build.sls as a macro that can be reused for many docs/versions
pillar.example wasn't an example so much as default values
Added build and service state files to README