• pr-979: Added visibilityOff icon and updated TextField to utilize it.
• issue-982: Updated Icon let declarations to var declarations to allow custom icon sets.
• issue-980: Added @objc to extension properties in Material+UIView.
• issue-650: Fixed issue where NavigationBar.backButton would incorrectly be laid out when caching view controllers.
• issue-973: Fixed issue where Button.prepare was not being called in the correct order.