Update pg package and convert data to correct type

No Issue
- Switch 'pg.js' package for 'pg' as the native bindings are
  now an optional add-on to pg and pg.js has been deprecated.
- pg@4.1.1
- Set the driver's parser to automatically convert integer data
  returned from postgres into a javascript integer.
Merge pull request #4676 from jaswilli/pg-update

Update pg package and convert data to correct type