Fix unit tests

Author: ivanlanin

tests/PhpWord/Tests/Element/CellTest.php

@@ -168,7 +168,7 @@ public function testAddImageSectionByUrl()
     {
         $oCell = new Cell();
         $element = $oCell->addImage(
-            'https://assets.mozillalabs.com/Brands-Logos/Thunderbird/logo-only/thunderbird_logo-only_RGB.png'
+            'http://php.net/images/logos/php-med-trans-light.gif'
         );
 
         $this->assertCount(1, $oCell->getElements());

tests/PhpWord/Tests/Element/FooterTest.php

@@ -119,7 +119,7 @@ public function testAddImageByUrl()
     {
         $oFooter = new Footer(1);
         $element = $oFooter->addImage(
-            'https://assets.mozillalabs.com/Brands-Logos/Thunderbird/logo-only/thunderbird_logo-only_RGB.png'
+            'http://php.net/images/logos/php-med-trans-light.gif'
         );
 
         $this->assertCount(1, $oFooter->getElements());

tests/PhpWord/Tests/Element/HeaderTest.php

@@ -128,7 +128,7 @@ public function testAddImageByUrl()
     {
         $oHeader = new Header(1);
         $element = $oHeader->addImage(
-            'https://assets.mozillalabs.com/Brands-Logos/Thunderbird/logo-only/thunderbird_logo-only_RGB.png'
+            'http://php.net/images/logos/php-med-trans-light.gif'
         );
 
         $this->assertCount(1, $oHeader->getElements());

tests/PhpWord/Tests/Writer/Word2007/PartTest.php

@@ -14,7 +14,7 @@
  * @copyright   2010-2014 PHPWord contributors
  * @license     http://www.gnu.org/licenses/lgpl.txt LGPL version 3
  */
-namespace PhpOffice\PhpWord\Tests\Writer\Word2007\Part;
+namespace PhpOffice\PhpWord\Tests\Writer\Word2007;
 
 use PhpOffice\PhpWord\Writer\Word2007\Part\RelsPart;
 
@@ -35,7 +35,7 @@ class PartTest extends \PHPUnit_Framework_TestCase
     public function testRelsWriteRelException()
     {
         $object = new RelsPart();
-        $object->setMedia(array(array('foo' => 'bar')));
+        $object->setMedia(array(array('type' => '', 'target' => '')));
         $object->write();
     }
 }