Fixe insert update removed dependency on primaryKey

*  This only changes AbstractRowGateway no other files are needed
*  InputFilter setting primaryKey to zero value so I couldn't test this for null or filter set's it to empty string
*  For Updating Basically you will need to populate the object with data before placing the 
changes from the "form" and then you can execute save() for the Db update.
*  Only needs to populate the originalData on Row Change
*  Examples bellow are from a Action Controller


My filter:
```PHP
 $inputFilter = new InputFilter();
            $factory     = new InputFactory();

            $inputFilter->add($inpt = $factory->createInput(array(
                'name'     => 'idsupplier',
                'required' => false,
                'filters'  => array(
                    array('name' => 'Int'),
                ),
            )));
            
            $inputFilter->add($factory->createInput(array(
                'name'     => 'name',
                'required' => true,
                'filters'  => array(
                    array('name' => 'StripTags'),
                    array('name' => 'StringTrim'),
                ),
                'validators' => array(
                    array(
                        'name'    => 'StringLength',
                        'options' => array(
                            'encoding' => 'UTF-8',
                            'min'      => 1,
                            'max'      => 254,
                        ),
                    ),
                ),
            )));

            $inputFilter->add($factory->createInput(array(
                'name'     => 'company',
                'required' => true,
                'filters'  => array(
                    array('name' => 'StripTags'),
                    array('name' => 'StringTrim'),
                ),
                'validators' => array(
                    array(
                        'name'    => 'StringLength',
                        'options' => array(
                            'encoding' => 'UTF-8',
                            'min'      => 1,
                            'max'      => 254,
                        ),
                    ),
                ),
            )));
            
            $inputFilter->add($factory->createInput(array(
                'name'     => 'idsuppliertype',
                'required' => true,
                'filters'  => array(
                    array('name' => 'Int'),
                ),
            )));
```

*Example add*

```PHP
public function addAction()
    {
        $form = new SupplierForm($this->getSupplierTypes());
        $form->get('submit')->setValue('Add');

        $request = $this->getRequest();
        if ($request->isPost()) {
            $supplier = new Supplier($this->getSupplierTable()->getAdapter());
            $form->setInputFilter($supplier->getInputFilter());
            $form->setData($request->getPost());

            if ($form->isValid()) {
                $supplier->populate($form->getData());
                $id = $supplier->save();

                // Redirect to list of albums
                return $this->redirect()->toRoute('supplier/list');
            }
        }
        return array('form' => $form);
    }
```
*Example Edit* 
```PHP
public function editAction()
    {
        $id = (int) $this->params()->fromRoute('id', 0);
        if (!$id) {
            return $this->redirect()->toRoute('supplier', array(
                'action' => 'add'
            ));
        }
        $supplierRow = $this->getSupplierTable()->fetchRow("idsupplier = " . (int) $id);
        $supplier = new Supplier($this->getSupplierTable()->getAdapter());

        $supplier->populateOriginalData((array)$supplierRow);

        $form = new SupplierForm($this->getSupplierTypes());
        $form->bind($supplierRow);
        $form->get('submit')->setAttribute('value', 'Edit');

        $request = $this->getRequest();
        if ($request->isPost()) {
            $form->setData($request->getPost());
            $form->setInputFilter($supplier->getInputFilter());
            if ($form->isValid()) {
                $supplier->populate((array)$supplierRow);
                $supplier->save();

                // Redirect to list of albums
                return $this->redirect()->toRoute('supplier');
            }
        }

        return array(
            'id' => $id,
            'form' => $form,
        );
    }
```

**This was based on akrabat code with changes to reduce my work.**