extracted plan visibility work out of dev branch for PR to DCC

fixed issue with settings data saved to the DB using an old version of the gem. stripped html tags from question text for display in the export form.

fixed issue with plan list column display issue

Added fix for issues when displaying column headings on the view plans page. Setup and 'Unknown' column heading that defaults to ' - ' but is updateable in the locale files. If there are issues determining the column heading it will use that value