adjust error messages on timeout of saving ajax requests

so far it is not clear enough to the user, that nothing is saved and he must not continue working, because translate5 adjusts the grid indepently of the success of the saving. Adjuzst in a way that points to the possiblity of connection problems.

Current message on timeout is: Fehler beim Speichern oder beim Auslesen von Daten. Bitte wenden Sie sich an unseren Support!

Meldung vom Server: 0 communication failure

This should be changed in a way that makes clear, that the server is not responding due to connection problems in the internet connection.