Make tests not fail when postgres has active connections to other databases on localhost server

If there are several active connections to the postgres server on localhost (which is used for unittests),
SELECT COUNT(*) FROM pg_stat_activity returns unexpected result. We need to see only number of connections to
the test database.
Make FormatColumnName public
Created pg/pgutil package, moved formatColumnName function there as Underscore()
Merge pull request #5 from Babazka/feature/make_formatColumnName_public

Make formatColumnName public