Merge pull request #231 from rickcarlino/master

opt in / out of mailing list
Make call to https for external js and css, and specify loading tag for loading button
Merge branch 'master' of https://github.com/FarmBot/OpenFarm into update-guides
Fixed #173. fix impressionist within guides.
responses to the hound
Merge pull request #233 from simonv3/update-guides

Fix Insecure reference to JS and CSS and specify .loading tag
Better
Merge conf.