modify docs for supporting multiple versions.
update docs help.txt and online instructions page;
use vars in _config.yml for version, rather than files in fields/* ;
include version in the top-right corner;
show versions ahead of governance in toc; and
make versions.md dependent on where we are running what it shows,
  and a place to list version history, key changes, etc
fix change-version to be simpler, more powerful, and more portable (multiline sed)
various files which required additional annotations for version updates
Merge pull request #442 from ahgittin/feature/versioned-docs

modify docs for supporting multiple versions.