This patch removes the InterceptedRequest.isHandled method. There's
always a single request interceptor who owns all the intercepted
requests and who know if they were handled.
References #115.
This patch:
- drops Request dependency on NetworkManager
- drops Response dependency on NetworkManager
- drops requestIds from Request and Response objects
This patch implements NetworkManager, which encapsulates all the
interaction with Network domain.
The NetworkManager also uses partial implementation of Request and
Response classes, defined in the Fetch API specification.
References #26