[This is a combination of 10 commits.
Original author:    yln <sourgrapes612@hotmail.com>]

Fixes for redmine issue #2162:

Added migration to add columns to the variables table and updated
index, show, edit, and new pages for variables to show and edit these
new fields to administrators.  Included a link to a CF guidelines
page.
Merge branch 'phenolphtalein-add_fields'