Add unregister to IoC-Contrainer

Signed-off-by: Steven Klar <steven.klar@mayflower.de>

laravel/tests/cases/ioc.test.php

@@ -28,6 +28,7 @@ class TestClassTwoForIoC
 	}
 }
 
+use \Laravel\IoC as IoC;
 
 class IoCTest extends PHPUnit_Framework_TestCase {
 
@@ -150,4 +151,17 @@ class IoCTest extends PHPUnit_Framework_TestCase {
 		$this->assertEquals(42, $class_two->class_one->test_variable);
 	}
 
+    public function testCanUnregisterRegistered()
+    {
+        $testClass = 'test';
+
+        IoC::register($testClass, function() {});
+
+        $this->assertTrue(IoC::registered($testClass));
+
+        IoC::unregister($testClass);
+
+        $this->assertFalse(IoC::registered($testClass));
+    }
+
 }