ilastik/applets/base/appletSerializer.py: Overrode shouldSerialize for SerialBlockSlot. This checks to make sure that all relevant groups and datasets are serialized. Required as SerialBlockSlot has a couple layers of nested groups and it is not obvious if it has been serialized without checking the full structure.
ilastik/applets/base/appletSerializer.py: Added shouldSerialize method to AppletSerializer. This tries to call shouldSerialize for all slots. Only happens if self.topGroupName is specified and the AppletSerializer is not already dirty.
ilastik/shell/projectManager.py: When check whether to serialize verify that shouldSerialize whether is True also.