postgresql 0.3.0+1

Postgresql database driver.

Version 0.3.0

• A new connection pool with more configuration options.
• Support for json and timestamptz types.
• Utc time zone support.
• User customisable type conversions.
• Improved error handling.
• Connection.onClosed has been removed.
• Some api has been renamed, the original names are still functional but marked as deprecated.
  • import 'package:postgresql/postgresql_pool.dart' => import 'package:postgresql/pool.dart'
  • Pool.destroy() => Pool.stop()
  • The constants were upper case and int type. Now typed and lower camel case to match the style guide.
  • Connection.unhandled => Connection.messages
  • Connection.transactionStatus => Connection.transactionState

Thanks to Tom Yeh and Petar Sabev for their helpful feedback.