message: chore: export more from redoc.module
diff: import { NgModule, ErrorHandler, APP_ID } from '@angular/core';
  import { CommonModule } from '@angular/common';
  +import { SpecManager } from './utils/spec-manager';
  +
  import { Redoc, SecurityDefinitions, Operation, REDOC_DIRECTIVES } from './components/index';
  -import { REDOC_COMMON_DIRECTIVES, DynamicNg2Wrapper } from './shared/components/index';
  +import { REDOC_COMMON_DIRECTIVES, DynamicNg2Wrapper, DropDown } from './shared/components/index';
  import { REDOC_PIPES } from './utils/pipes';
  import { CustomErrorHandler } from './utils/'
  import { LazyTasksService } from './shared/components/LazyFor/lazy-for';
  import {
  OptionsService,
  + Options,
  MenuService,
  ScrollService,
  Hash,
  @@ -19,10 +22,9 @@ import {
  Marker,
  SchemaHelper,
  SearchService,
  + MenuItem,
  COMPONENT_PARSER_ALLOWED } from './services/';
  -import { SpecManager } from './utils/spec-manager';
  -
  @NgModule({
  imports: [ CommonModule ],
  declarations: [ REDOC_DIRECTIVES, REDOC_COMMON_DIRECTIVES, REDOC_PIPES ],
  @@ -49,6 +51,7 @@ export { Redoc, SpecManager, ScrollService,
  Hash,
  WarningsService,
  OptionsService,
  +Options,
  AppStateService,
  ComponentParser,
  ContentProjector,
  @@ -56,4 +59,5 @@ MenuService,
  SearchService,
  SchemaHelper,
  LazyTasksService,
  -Marker };
  +MenuItem,
  +Marker, DropDown };
  