[SoapBundle] Moved configuration of ComplexType aliases from config to PHP objects with annotations

Before:
``` yaml
be_simple_soap:
    services_classmap:
        Cutomer: My\Bundle\Entity\Customer
        Cart:    My\Bundle\Entity\Cart

After:
``` php
<?php

namespace My\Bundle\Entity;

use BeSimple\SoapBundle\ServiceDefinition\Annotation as Soap;

/**
 * @Soap\Alias("Customer")
 */
class Customer
{
    // ... your PHP code
}

/**
 * @Soap\Alias("Cart")
 */
class Cart
{
    // ... your PHP code
}

src/BeSimple/SoapBundle/ServiceDefinition/Annotation/Alias.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file is part of the BeSimpleSoapBundle.
+ *
+ * (c) Christian Kerl <christian-kerl@web.de>
+ * (c) Francis Besset <francis.besset@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace BeSimple\SoapBundle\ServiceDefinition\Annotation;
+
+/**
+ * @Annotation
+ */
+class Alias extends Configuration
+{
+    private $value;
+
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    public function setValue($value)
+    {
+        $this->value = $value;
+    }
+
+    public function getAliasName()
+    {
+        return 'alias';
+    }
+}

src/BeSimple/SoapBundle/ServiceDefinition/Annotation/Configuration.php

@@ -21,10 +21,10 @@ abstract class Configuration implements ConfigurationInterface
     {
         foreach ($values as $k => $v) {
             if (!method_exists($this, $name = 'set'.$k)) {
-                throw new \RuntimeException(sprintf('Unknown key "%s" for annotation "@%s".', $k, get_class($this)));
+                throw new \RuntimeException(sprintf('Unknown key "%s" for annotation "@%s".', $k, __CLASS__));
             }
 
             $this->$name($v);
         }
     }
-}
+}