Postgresql Adapter

[klemens-morgenstern]

Heya, I've wrote an adapter for Postgres that replicates the schema, so I can use nanoSQL as a faster memory-buffer. I'd be interested in hearing some feedback!

I hope I got all functions right, I am not sure about the deleteIndexValue one. Tests pass locally, though.

I also fear my codestyle got a bit sloppy through all the trial & error, so please point out unreadable pieces.