Include utility for std::pair
Hide postgresql notices

By using client_min_messages we can hide notices we expect to occur.
Add more missing includes for std::pair

Although these aren't causing errors, it adds clarity anyways and may reduce
future problems.
Merge pull request #198 from pnorman/utility

Include utility for std::pair
Merge pull request #205 from pnorman/client_min_messages

Hide postgresql notices