[SalesForce] Winter 18 does not get values from a parent record

I am testing the new <lightning:datatable>, it is really good, and is a good replacement for most of my use cases which today I use a custom list component that I have developed.

I am getting data from my server through apex method, to populate it into the <lightning:datatable> component. I can bind the returned list directly to the data attribute and if the column names are same as the field names, all data is bound correctly.

The problem occurs when I get data from a parent record. For example – I want the Account name of my contact.

This example can show the problem:

Component Markup

<aura:handler name="init" value="{!this}" action="{!c.doInit}"/>

<aura:attribute name="mydata" type="Object"/>
<aura:attribute name="mycolumns" type="List"/>
<aura:attribute name="sortedBy" type="String"/>
<aura:attribute name="sortedDirection" type="String"/>

<lightning:datatable data="{! v.mydata }"
                     columns="{! v.mycolumns }"
                     keyField="Id"
                     onrowselection="{! c.getSelectedName }"
                     onsort="{!c.updateColumnSorting}"
                     sortedBy="{!v.sortedBy}"
                     sortedDirection="{!v.sortedDirection}"
                     hideCheckboxColumn="{!false}"
/>

Component Controller

({
    doInit: function (component, event, helper) {
        component.set('v.mycolumns', [
                    {label: 'Id', fieldName: 'Id', type: 'id', sortable:"true"},
                    {label: 'First Name', fieldName: 'FirstName', type: 'text', sortable:"true"},
                    {label: 'Last Name', fieldName: 'LastName', type: 'text', sortable:"true"},
                    {label: 'First Name Hebrew', fieldName: 'First_name_Hebrew__c', type: 'text', sortable:"true"},
                    {label: 'Last Name Hebrew', fieldName: 'Last_name_Hebrew__c', type: 'text', sortable:"true"},
                    {label: 'Account', fieldName: 'Account.Name', type: 'text', sortable:"true"},
                    {label: 'Email', fieldName: 'Email', type: 'email', sortable:"true"},
                    {label: 'Phone', fieldName: 'Phone', type: 'phone', sortable:"true"}
                ]);

        var action = component.get("c.getRecordsFromDb");
        action.setParams({
            sObjectName: "Contact",
            commaDelimitedFieldNames: "Id,FirstName,LastName,First_name_Hebrew__c,Last_name_Hebrew__c,Account.Name,Email,Phone",
            filter: ""
        });
        action.setCallback(this, function(response){
            var state = response.getState();
            if (component.isValid() && state === "SUCCESS") {
                var data = response.getReturnValue();

                component.set("v.mydata", data);
            }
        });
        $A.enqueueAction(action);
    }
})

APEX Aura Enabled Method

@AuraEnabled
public static List<sObject> getRecordsFromDb(String sObjectName,
        String commaDelimitedFieldNames,
        String filter) {

    system.debug('\n\n\n\ngetRecordsFromDb sObjectName: ' + sObjectName + ', commaDelimitedFieldNames: ' + commaDelimitedFieldNames + ', filter: ' + filter + '\n\n\n\n');

    // create a dynamic soql to get the value of the field
    String sql = 'SELECT ' + commaDelimitedFieldNames + ' FROM ' + sObjectName;

    if (!String.isBlank(filter))
        sql += ' WHERE ' + filter;

    system.debug('\n\n\n\ngetRecordsFromDb sql: ' + sql + '\n\n\n\n');
    List<sObject> records = Database.query(sql);
    system.debug('\n\n\n\ngetRecordsFromDb: ' + records + '\n\n\n\n');

    return records;
}

The problem is with the Account.Name field – the <lightning:datatable> component does not display the column data.

I know that the data is returned ok, and I know that in the object that is returned, the Account is contained like an object (probably this is the problem):

Is there a good way to show parent record data with this component?