Added support for optional field `msg` in `GetSchemaResponse` and `GetUserSchemaResponse`
Fixed error handling for generic (non-API-related) errors
Group attrs as HashMap, delete with all_content, GL pipeline for tests
Omit `authorize` in the Permissions JSON if the `authorize` list is empty
Add parameter uid_type for OAuth Introspect endpoint
Updated version of OkHttp3 library to prevent bug on Android
Deprecated code: old Search API, old Permissions interface, unused classes
Fixed parsing of 'Permissions.ResourceType' and tests