Provide option to interpret dates as UTC

[johnfrench3]

Looking at brianc/node-postgres#510, it appears that dates used to be interpreted as UTC, but then there was a decision made to interpret them as system time. In my experience interpreting dates and timestamps in system timezone is very fragile. Even having to set the system clock to UTC is not always possible. It's an even bigger problem when the application needs to handle multiple timezones.

The rule of thumb we use is to always use UTC internally. Only the user interface layer deals with local timezone and converts it to UTC on input and local timezone on output. This allows the app to be extremely portable - no need to worry about system time or local timezone of the client machine.

I was wondering if there is a way to provide an option to interpret dates as UTC or system timezone. This will make sure that backward compatibility is maintained but make the library flexible to cater for different use cases.