Methods removed from ReadGraph interface, also removed those org.simantics.interop...

Methods removed from ReadGraph interface, also removed those org.simantics.interop.mapping implementations.
* public void forEachDirectObject(final Resource subject, final Resource relation, final AsyncMultiProcedure<Resource> procedure)
* public void forEachDirectObject(final Resource subject, final Resource relation, final MultiProcedure<Resource> procedure)
* public void forEachDirectObject(final Resource subject, final Resource relation, final SyncMultiProcedure<Resource> procedure)

refs #3526

git-svn-id: https://www.simantics.org/svn/simantics/interoperability/trunk@25233 ac1ea38d-2e2b-0410-8846-a27921b304fc