Fixing strict standards warning

Strict standards: Declaration of ImagineUtilityTest::startTest() should be compatible with CakeTestCase::startTest($method) in /.../app/Plugin/Imagine/Test/Case/Lib/ImagineUtilityTest.php on line 14

Strict standards: Declaration of ImagineUtilityTest::endTest() should be compatible with CakeTestCase::endTest($method) in /.../app/Plugin/Imagine/Test/Case/Lib/ImagineUtilityTest.php on line 14