Formatting
API client setup
Keychain entitlements
Proper API endpoint (with https: scheme)
API client: set response serializer in init, use Accept header instead
of .json path extension
Using patched GROAuth2SessionManager from @corristo/GROAuth2SessionManager
Designated initializer FTW
Login: use non-expiring token
Saving/loading token from to/from keychain, simple activity request is
executed if token is present