ACTION-236: Add ECKey value as child of KeyValueType

All,

This is the proposed change for ACTION-236, intended only to clarify where 
ECKeyValues will be carried in elements of type ds:KeyValueType.

In section 4.4.2, propose to change from:

     <element name="KeyValue" type="ds:KeyValueType"/>
     <complexType name="KeyValueType" mixed="true">
      <choice>
        <element ref="ds:DSAKeyValue"/>
        <element ref="ds:RSAKeyValue"/>
        <any namespace="##other" processContents="lax"/>
      </choice>
     </complexType>

to:

     <element name="KeyValue" type="ds:KeyValueType"/>
     <complexType name="KeyValueType" mixed="true">
      <choice>
        <element ref="ds:DSAKeyValue"/>
        <element ref="ds:RSAKeyValue"/>
        <!-- <element ref="dsig11:ECKeyValue"/> -->
        <!-- ECC keys (XMLDsig 1.1) will use the any element -->
        <any namespace="##other" processContents="lax"/>
      </choice>
     </complexType>


(BTW, should the DTD section be updated?)

-- Magnus