DbInfoCode upgrade 3.1.0: multiple datasets with dropdown choice

I must confess that the postgresql integration is not yet there, made a start though, help welcome.
Multiple dataset with drop-down box seems to work somewhat, might need bugfixes.
What works for me is that I can switch between two datasets on my laptop (both locahost, one is mysql other is postgresql - but see note above on the use).
Purpose of this change is switching is between development on localhost an production on remote host.