Add Export option to only include objects directly referenced by the export object

Currently the Include All Referenced Objects option propagates down to each referenced object. This can lead to excessively large xml files for the export of a relatively simple object. For example, exporting an AFEventFrame that references an element several levels deep in the hierarchy will require an export of each element in the path to the referenced element. However, because Include All Referenced Objects is propagated to each of these elements, the entire hierarchy under the root element will be exported along with relevant templates and other objects. For the sake of performance and efficiency it would be useful to have an option that only includes the objects strictly necessary to fully reproduce the exported object. For the AFEventFrame example, this would include all the elements in the path to the referenced element and anything required to import them without error, but would exclude other elements not found directly in the path (and thus not necessary to import the AFEventFrame without errors).