Add a G_FILE_MONITOR_SEND_MOVED flag indicating the API user wants to receive the new G_FILE_MOINOTR_EVENT_MOVED event instead of single CREATED/DELETED events. First part of bug #547890.
Previously, the code had a heisenbug and could potentially return superclasses, too. In fact, it was based on the behavior of malloc. https://bugzilla.redhat.com/show_bug.cgi?id=554678
Also convert GLocalFileIOStream to use the new interface to obtain the file descriptor.