PIDF - schema - one in ID has key line removed

The schema in the ID had the import line removed (near the top).  It isn't
valid without that line - xml:lang doesn't work without it.  I also added
the extension at the top level.  Extensions are used there in the examples.

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   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema targetNamespace="urn:ietf:params:xml:ns:cpim-pidf:"
        xmlns:tns="urn:ietf:params:xml:ns:cpim-pidf:"
        xmlns:xs="http://www.w3.org/2001/XMLSchema"
        elementFormDefault="qualified"
        attributeFormDefault="unqualified">

    <!-- This import brings in the XML language attribute xml:lang-->
    <xs:import namespace="http://www.w3.org/XML/1998/namespace"   
        schemaLocation="http://www.w3.org/2001/xml.xsd"/>

      <xs:element name="presence" type="tns:presence"/>

      <xs:complexType name="presence">
         <xs:sequence>
            <xs:element name="tuple" type="tns:tuple"
maxOccurs="unbounded"/>
            <xs:element name="note" type="xs:string" minOccurs="0"
                maxOccurs="unbounded"/>
            <xs:any namespace="##other" processContents="lax" minOccurs="0"
               maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:attribute name="entity" type="xs:anyURI" use="required"/>
      </xs:complexType>

      <xs:complexType name="tuple">
         <xs:sequence>
            <xs:element name="status" type="tns:status"/>
            <xs:any namespace="##other" processContents="lax" minOccurs="0"
               maxOccurs="unbounded"/>
            <xs:element name="contact" type="tns:contact" minOccurs="0"/>
            <xs:element name="note" type="xs:string" minOccurs="0"
               maxOccurs="unbounded"/>
            <xs:element name="timestamp" type="xs:dateTime" minOccurs="0"/>

         </xs:sequence>
         <xs:attribute name="id" type="xs:ID" use="required"/>
      </xs:complexType>

      <xs:complexType name="status">
         <xs:sequence>
            <xs:element name="basic" type="tns:basic" minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax" minOccurs="0"
               maxOccurs="unbounded"/>
         </xs:sequence>
      </xs:complexType>

      <xs:simpleType name="basic">
         <xs:restriction base="xs:string">
            <xs:enumeration value="open"/>
            <xs:enumeration value="closed"/>
         </xs:restriction>
      </xs:simpleType>

      <xs:complexType name="contact">
         <xs:simpleContent>
            <xs:extension base="xs:anyURI">
               <xs:attribute name="priority" type="xs:unsignedByte"/>
            </xs:extension>
         </xs:simpleContent>
      </xs:complexType>

      <xs:complexType name="note">
         <xs:simpleContent>
            <xs:extension base="xs:string">
               <xs:attribute ref="xml:lang"/>
            </xs:extension>
         </xs:simpleContent>
      </xs:complexType>

      <!-- Global Attributes -->
      <xs:attribute name="mustUnderstand" type="xs:boolean" default="0"/>
   </xs:schema>


  [reminder: [email protected] for non-technical discussions, please]