[gen] Added field.persist to avoid storing values for fields that do not require it (like master fields only used to determine selectable values among slave fields).

gen/wrappers/ToolWrapper.py

@@ -141,9 +141,10 @@ class ToolWrapper(AbstractWrapper):
     </x>''')
 
     pxPageBottom = Px('''
-     <script type="text/javascript">:'initSlaves(%s,%s,%s)' % \
-                    (q(zobj.absolute_url()), q(layoutType), \
-                     zobj.getSlaveFieldsRequestValues(page))</script>''')
+     <script var="info=zobj.getSlavesRequestInfo(page)"
+             type="text/javascript">:'initSlaves(%s,%s,%s,%s)' % \
+                    (q(zobj.absolute_url()), q(layoutType), info[0], info[1])
+     </script>''')
 
     pxPortlet = Px('''
      <x var="toolUrl=tool.url;

gen/wrappers/__init__.py

@@ -533,7 +533,7 @@ class AbstractWrapper(object):
 
     pxEdit = Px('''
      <x var="x=zobj.allows('write', raiseError=True);
-             errors=req.get('errors', None) or {};
+             errors=req.get('errors', {});
              layout=zobj.getPageLayout(layoutType);
              cssJs={};
              phaseObj=zobj.getAppyPhases(currentOnly=True, \