Read restriction child sequences

[veewee]

Hello,

This PR accepts restriction overrides like <all>

<xs:complexType name="testType">
    <xs:complexContent>
        <xs:restriction base="tns:Array">
            <xs:all>
                <xs:element name="x_item" type="xs:int" maxOccurs="unbounded" />
            </xs:all>
        </xs:restriction>
    </xs:complexContent>
</xs:complexType>

The overridden elements will now be available on the elements of the testType complex-type.

[Guite]

Hi @veewee and thank you very much for your contribution. This looks fine for us, so I will happily merge it.