message: add IComponent<T> back to apprun.d.ts
diff: @@ -6,6 +6,12 @@ declare module 'apprun' {
  export type Action<T> = (state: T, ...p: any[]) => T | Promise<T>;
  export type Update<T> = { [name: string]: Action<T> | {}[] | void; };
  + export class IComponent<T> {
  + readonly state: T;
  + view: View<T>;
  + update: Update<T>;
  + }
  +
  export type VNode = {
  tag: string,
  props: {},
  @@ -23,7 +29,7 @@ declare module 'apprun' {
  export class Component<T> {
  constructor(state?: T, view?: View<T>, update?: Update<T>);
  - state: T;
  + readonly state: T;
  setState(state: T, options?: { render?: boolean, history?: boolean }): void;
  mount(element?: Element, options?: { render?: boolean, history?, global_event?: boolean }): Component<T>;
  start(element?: Element, options?: { render?: boolean, history?, global_event?: boolean }): Component<T>;
  