- use OF signals for object updates

- invoke of ""viewAll" moved from the end of the reader to "openedFile" slot, as every reader invoked it but openedFile just, if only one object was loaded
- prepares asnyc load

refs #2421

git-svn-id: http://www.openflipper.org/svnrepo/OpenFlipper/branches/Free@20986 383ad7c9-94d9-4d36-a494-682f7c89f535