List of objects

Please view the related PR in BeSimpleSoapBundle, BeSimpleSoapCommon, BeSimpleSoapWsdl

The goal of this PR is to fix the problem described here :
https://github.com/BeSimple/BeSimpleSoap/issues/48

With this PR it's possible to define a collection of object like this:
```php
/**
 * @Soap\Alias("ParticipantTypeDetail")
 */
class ParticipantTypeDetail
{
    /**
     * @var string
     * @Soap\ComplexType("string")
     */
    private $name;

    /**
     * @var ParticipantTypeProperty[]
     * @Soap\ComplexType("PTC\WsBundle\TO\ParticipantProperty", minOccurs="1", maxOccurs="unbounded")
     */
    private $participantList;
```

The related generated WSDL is:
```
<xsd:complexType name="ParticipantTypeDetail">
    <xsd:all>
        <xsd:element name="name" type="xsd:string"/>
        <xsd:element name="participantList" type="tns:ParticipantProperty" minOccurs="1" maxOccurs="unbounded"/>
    </xsd:all>
</xsd:complexType>
```

Sample of response from a WS Call:
```
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://organisation.novento-reloaded.eu/ws/MobileApi/1.0/">
   <SOAP-ENV:Body>
      <ns1:getParticipantTypeDetailsResponse>
         <return>
            <name>Supplier</name>
            <participantList>
               <id>12</id>
               <firstName>Thomas</firstName>
               <lastName>Lallement</lastName>
               <organisation>Decostanding</organisation>
               <position>Driver</position>
               <participationStatusClass>accredited</participationStatusClass>
            </participantList>
            <participantList>
               <id>22</id>
               <firstName>Jerome</firstName>
               <lastName>Martin</lastName>
               <organisation>Decostanding</organisation>
               <position>Fire departement</position>
               <participationStatusClass>requested</participationStatusClass>
            </participantList>
         </return>
      </ns1:getParticipantTypeDetailsResponse>
   </SOAP-ENV:Body>
</SOAP-ENV:Envelope>
```

So from the client side we can fetch the results by doing (sample with PHP Classmap)
```php
$participantList = $myObject->getParticipantList();
```

Rather than (current behavior):
```php
$participantList = $myObject->getParticipantList()->item;
```