Remove unnecessary event box listener

Since the event box is an ordinary viewable there is no need for an
event box listener anymore.
Fixed update method in abstract mapper

The abstract mapper still had an old left over from previous versions
that kept it from working properly. The reason for the bug was that the
key did not get loaded while doing updates, some confuscating error that
now luckily has been found.
Merge remote-tracking branch 'origin/master'
Finally fixing the update method in abstract mapper

The correct position of the conditional key has to be calculated
properly. This has been accomplished by the geUpdateColumnSize method of
the entity table.
Fixed database abstraction logic

The mapper still was having problems, concerning the indexes of
statement positions. One major logical error was the assumption, that
the key columns equals the ones found within the table - in fact only
the name is the same, not the entire column.