Allow version-specific config values, fix for unwanted space on right

The config.yml file can now have settings overridden based on version.  For example:

tag-links-domain: 'mydomain.com'
owners:
  tag-links: 's_emailid=my_owners_tag'
prospects:
  tag-links: 's_emailid=my_prospects_tag'

Also, this includes the fix for the unwanted right-side space in mobile versions of the email on select iOS devices.