Support for http interceptors, retry, timeout, parsing

In my opinion this library misses some basic functionality as of 2018.

Among them I would definately say http interceptors, a retry/retryWithDelay functionality and a timeout or cancel mechanism.
Additionally it would be a nice to have to offer an automated parsing of the response, upload progress, and maybe some form of error extraction.

Some hints on additional functionality might be derived from the angular/common library as they have imo a very capable http client (https://github.com/angular/angular/tree/master/packages/common/http/src)