declareDecorator does not bring along getters and setters

[schontz]

If you use the declareDecorator on a class all the getters and setters are lost.

I was having issues making a PR so here is the updated version of https://github.com/dojo/typings/blob/master/examples/basicApp/src/app/declareDecorator.ts:

import dojoDeclare from 'dojo/_base/declare';

/**
 * A decorator that converts a TypeScript class into a declare constructor.
 * This allows declare constructors to be defined as classes, which nicely
 * hides away the `declare([], {})` boilerplate.
 */

export default function (... mixins: Object[]) {
    return function (target: Function) {
        let declared = dojoDeclare(mixins, target.prototype);

        // Bring getters and setters along for the ride
        Object.keys(target.prototype).forEach(key => {
            let descrip = Object.getOwnPropertyDescriptor(target.prototype, key);
            if (typeof descrip.get == 'function' || typeof descrip.set == 'function') {
                Object.defineProperty(declared.prototype, key, descrip);
            }
        });

        return declared;
    };
}