* Created definitions for promise-pg
Dependencies:
* node
* Q
* pg
Tests script is cribbed from pg typings and modified for promise-pg.
'promise-pg'.Client does not inherit from 'pg'.Client because the
functions redefined to return promises completely replace the originals
from 'pg'.
* fix: QueryConfig.buffer is optional
It's only needed when doing a SELECT anyway, so mark it optional.
* Bring promise-pg tests in line with examples from promise-pg readme
* Add the promise-pg readme examples as tests
