Merge pull request #25 from alfreddatakillen/diffcolor

Diffcolor
Merge pull request #27 from alfreddatakillen/dupenotifications

Notify user when the same option is stored in more than one bundle
Merge pull request #28 from alfreddatakillen/downloadlink

Download link
Ensure that old_value exists, even if empty (#26)
Bulk tweaks
Multisite support for WPCFM()->readwrite->delete_file
merge fix