message: use !isNaN for isNumber
diff: @@ -156,7 +156,7 @@ namespace MakerJs {
  * @returns True if the object is a number type.
  */
  export function isNumber(value: any): boolean {
  - return typeof value === 'number';
  + return !isNaN(value);
  }
  /**
  @@ -785,7 +785,7 @@ namespace MakerJs {
  */
  export function isChain(item: any): boolean {
  var x = item as IChain;
  - return x && x.links && Array.isArray(x.links) && !isNaN(x.pathLength);
  + return x && x.links && Array.isArray(x.links) && isNumber(x.pathLength);
  }
  /**
  