tileExists2 no longer uses the filename argument

Like this the call would throw an exception as fromThread would effectively
be defined twice.
Tweak message generation

Make it possible to get message without name for saving as description
to the POI database.
Fix saving of local search results to POI database

It has been broken by the switch to the new local search API,
but now works again and should be now also more flexible
and easier to use with other local search providers (uses the Point object).