message: added "defineLayout" and other updates
diff: @@ -16,7 +16,7 @@ export = PptxGenJS
  declare class PptxGenJS {
  /**
  - * Library Version
  + * PptxGenJS Library Version
  */
  readonly version: string
  @@ -24,12 +24,14 @@ declare class PptxGenJS {
  /**
  * Presentation layout name
  - * Available Layouts:
  - * 'LAYOUT_4x3' (10" x 7.5")
  - * 'LAYOUT_16x9' (10" x 5.625")
  - * 'LAYOUT_16x10' (10" x 6.25")
  - * 'LAYOUT_WIDE' (13.33" x 7.5")
  - * 'LAYOUT_USER' (user specified, can be any size)
  + * Standard layouts:
  + * - 'LAYOUT_4x3' (10" x 7.5")
  + * - 'LAYOUT_16x9' (10" x 5.625")
  + * - 'LAYOUT_16x10' (10" x 6.25")
  + * - 'LAYOUT_WIDE' (13.33" x 7.5")
  + * Custom layouts:
  + * Use `pptx.defineLayout()` to create custom layouts (e.g.: 'A4')
  + * @type {string}
  * @see https://support.office.com/en-us/article/Change-the-size-of-your-slides-040a811c-be43-40b9-8d04-0de5ed79987e
  */
  layout: string
  @@ -41,6 +43,10 @@ declare class PptxGenJS {
  // Presentation Metadata
  author: string
  company: string
  + /**
  + * @type {string}
  + * @note the `revision` value must be a whole number only (without "." or "," - otherwise, PPT will throw errors upon opening!)
  + */
  revision: string
  subject: string
  title: string
  @@ -54,6 +60,13 @@ declare class PptxGenJS {
  */
  addSlide(masterSlideName?: string): PptxGenJS.Slide
  /**
  + * Define a custom Slide Layout
  + * @example pptx.defineLayout({ name:'A3', width:16.5, height:11.7 });
  + * @see https://support.office.com/en-us/article/Change-the-size-of-your-slides-040a811c-be43-40b9-8d04-0de5ed79987e
  + * @param {IUserLayout} layout - an object with user-defined w/h
  + */
  + defineLayout(layout: PptxGenJS.IUserLayout): void;
  + /**
  * Adds a new slide master [layout] to the Presentation
  * @param {ISlideMasterOptions} slideMasterOpts - layout definition
  */
  @@ -509,6 +522,11 @@ declare namespace PptxGenJS {
  width?: number
  height?: number
  }
  + export interface IUserLayout {
  + name: string;
  + width: number;
  + height: number;
  + }
  export interface ISlideNumber extends PositionOptions {
  fontFace?: string
  fontSize?: number
  