280: Particle System is broken because of AttributeError

[tngreene]

This is really silly.

objs = self.xplaneFile.objects

                if not list(filter(lambda obj: obj[1].type == "EMPTY" and\
                        obj[1].blenderObject.xplane.special_empty_props.special_type == EMPTY_USAGE_EMITTER_PARTICLE or\
                        obj[1].blenderObject.xplane.special_empty_props.special_type == EMPTY_USAGE_EMITTER_SOUND,\
                        objs.items())):

when we changed from xplaneFile.objects to xplaneFile.get_xplane_objects we started returning a list instead of a dict. Here's the fix.

                objs = self.xplaneFile.get_xplane_objects()

                if not list(filter(lambda obj: obj.type == "EMPTY" and\
                        obj.blenderObject.xplane.special_empty_props.special_type == EMPTY_USAGE_EMITTER_PARTICLE or\
                        obj.blenderObject.xplane.special_empty_props.special_type == EMPTY_USAGE_EMITTER_SOUND,\
                        objs)):

This would have been very easily caught by fixing the unit test for this. #493 .