ULib - This patch adds PostGres test alongside with minor fix

This patch adds PostGres test database alongside with minor fix...

All tests are passing as per [my Travis-CI build log](https://travis-ci.org/stefanocasazza/FrameworkBenchmarks/builds/45049685)
You can also do this, which looks a bit cleaner to me

`sed -i "s|PREFORK_CHILD .*|PREFORK_CHILD ${MAX_THREADS}|g" $ULIB_ROOT/benchmark.cfg`