I have idea we can set product status using following code in magento 1.x.but I’m not able to identify in magento 2.0 beta. i'm spending lot of time to search status.php file. i find following file.but no use.
magento2/app/code/Magento/Catalog/Model/Product/Attribute/Source/Status.php
$productid=10;// product id which you want to change status;
$storeid=1
Mage::getModel('catalog/product_status')->updateProductStatus($productid, $storeid, Mage_Catalog_Model_Product_Status::STATUS_ENABLED);