Updated tags for all XSDs

public/FWEArea/v2.1/XSD/FWEArea.xsd

@@ -92,7 +92,7 @@
   </element>
   <complexType name="FWEAreaType">
     <complexContent>
-      <extension base="core:_CityObjectType">
+      <extension base="core:AbstractCityObjectType">
         <sequence>
           <element minOccurs="0" name="fweAreaName" type="string">
             <annotation>

public/FWESystem/v2.1/XSD/FWESystem.xsd

@@ -45,7 +45,7 @@
   </element>
   <complexType name="FWESystemType">
     <complexContent>
-      <extension base="core:_CityObjectType">
+      <extension base="core:AbstractCityObjectType">
         <sequence>
           <element minOccurs="0" name="fweSystemName" type="string">
             <annotation>