Enable/Disable 3rd-party libraries

To improve user experience, we are using a couple of 3rd party libraries. 

Google Fonts - used in the Form Editor and for the "Custom fonts" in the Email Editor. This can be individually disabled by a filter.

Mixpanel - used to send anonymous data about the usage of the MailPoet plugin when you agreed with sharing the data.

Satismeter - used to ask for feedback.

You can stop loading all these libraries by disabling this option in the MailPoet's Settings > Advanced > Load 3rd-party libraries.