GAM 4.98

• Improved setup process with less steps. Consent screen is now automatically configured. Admin console domain-wide delegation now pre-populates client_id and scopes fields. Thanks to @marywholey.
• GAM now requires Python 3.6 or newer. 3.5 is no longer supported. This allows GAM to take advantage of modern Python language performance and readability improvements like f-strings. Thanks to @taers232c for converting many strings.
• More work by @ejochman to break gam.py into smaller modules and add testing.
• Various fixes and minor improvements.