findByAnd update: <#assign /> broken

[Adam Heath]

Why do SimpleMethod.java and ModelScreen.java both do 
context.put("null", GenericEntity.NULL_FIELD)?  That changes *all* null 
values in freemarker into that static instance, even when the target 
type of the variable is *not* going to be part of some entity-like map.

If I remove both of those calls(actually, remove one, change the other 
to place it as "nullField"), then the broken ordermgr link given earlier 
starts to finally work.  And, I think that even the nullField constant 
should not be removed, as NullField should only be used internally by 
the entity engine.