Derived property "data" should emit "change" events

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As a developer, I want to create a form view and only listen to changes of its "data" property, so that I can conveniently handle data changes.

This is especially useful for forms that autosave on data change and forms with dynamic fields.

Currently the "data" property is a cached derived property that will never emit any events. The documentation states otherwise:

https://www.npmjs.com/package/ampersand-form-view#properties

The following are FormView observables, thus emit "change" events:

valid - the valid state of the form
data - form field view values in { fieldName: value, fieldName2: value2 } format

Possible solution: Extend the update method to also trigger a "change" event passing the "data" property.

[countzero]

A possible workaround until this feature is implemented:

'use strict';

var AmpersandFormView = require('ampersand-form-view');

/**
 * Form View
 *
 * @see https://github.com/AmpersandJS/ampersand-form-view/blob/v7.0.0/ampersand-form-view.js
 * @see https://github.com/AmpersandJS/ampersand-form-view/issues/69
 */
module.exports = AmpersandFormView.extend({

    /**
     * Monkey patch the update method to trigger "change"
     * events on the cached derived property "data".
     *
     * @param {string} field The form fields.
     */
    update: function (field) {

        AmpersandFormView.prototype.update.call(this, field);

        this.trigger('change change:data', this.data);
    },
});