workflow: include an empty item in "Default State"

... otherwise when nothing is selected it looks like something is set.

Also translate and sort output.

bt5/erp5_workflow/SkinTemplateItem/portal_skins/erp5_workflow/Workflow_viewVariableList/my_state_base_category.xml

@@ -10,8 +10,8 @@
             <key> <string>delegated_list</string> </key>
             <value>
               <list>
-                <string>title</string>
                 <string>items</string>
+                <string>title</string>
               </list>
             </value>
         </item>
@@ -71,6 +71,10 @@
                     <key> <string>target</string> </key>
                     <value> <string></string> </value>
                 </item>
+                <item>
+                    <key> <string>title</string> </key>
+                    <value> <string></string> </value>
+                </item>
               </dictionary>
             </value>
         </item>
@@ -86,6 +90,12 @@
                     <key> <string>form_id</string> </key>
                     <value> <string>Base_viewFieldLibrary</string> </value>
                 </item>
+                <item>
+                    <key> <string>items</string> </key>
+                    <value>
+                      <list/>
+                    </value>
+                </item>
                 <item>
                     <key> <string>target</string> </key>
                     <value> <string>Click to edit the target</string> </value>
@@ -102,16 +112,13 @@
   </record>
   <record id="2" aka="AAAAAAAAAAI=">
     <pickle>
-      <tuple>
       <global name="TALESMethod" module="Products.Formulator.TALESField"/>
-        <tuple/>
-      </tuple>
     </pickle>
     <pickle>
       <dictionary>
         <item>
             <key> <string>_text</string> </key>
-            <value> <string>python: [(x.getTitleOrId(), x.getId()) for x in here.portal_categories.contentValues()]</string> </value>
+            <value> <string>python: [(\'\', \'\')] + sorted([(x.getCompactTranslatedTitle(), x.getId()) for x in here.portal_categories.contentValues()])</string> </value>
         </item>
       </dictionary>
     </pickle>