So far the first call to the API was a call to the OpenConnection method.
Without an OpenConnection some methods issued a cryptic "Object variable not set" Basic run-time message.
It is now intercepted to make it clearer.

A number of features are not database related: error handling, events handling, windows move/resize, dialogs, ...
They have been identified and adapted to be callable without database connection.
As such they are callable from any LO component, not only Base.

Change-Id: I99f408c8404a6192149747228b2b8493b9df5ae3
Reviewed-on: https://gerrit.libreoffice.org/10883Reviewed-by: Jean-Pierre Ledure <jp@ledure.be>
Tested-by: Jean-Pierre Ledure <jp@ledure.be>