Release 2.0.0

— The library now provides both synchronous and asynchronous APIs (see Introduction and API Reference)
— Multiple HTTP libraries are supported by default (see Available Session Implementations for the full list)
— It is now possible to add support for any HTTP library (see Session Interface)
— requests is now an optional dependency (although it's still used by default for synchronous API)
— Note that now requests-specific arguments must be passed differently (see Available Session Implementations)
— Preferred HTTP client libraries must be explicitly installed now (see Introduction)
— Client.upload() and Client.upload_by_link() can now accept a function that returns an iterator (or a generator) as a payload