message: improvements - marbles.spec-util - TS lint fixes
diff: import { Observable, OperatorFunction, from } from 'rxjs';
  import { TestScheduler } from 'rxjs/testing';
  -import { Effect, EffectResponse } from '../effects/effects.interface';
  +import { Effect } from '../effects/effects.interface';
  import { HttpRequest, HttpResponse } from '../http.interface';
  -type _ = EffectResponse;
  type MarbleFlow = [string, object];
  type MarbleDependencies = { response: HttpResponse, error?: Error };
  