Implement a connection property to add SQL text and bind values to PSQLException

[vlsi]

Currently pgjdbc does not put SQL text to the error messages.
That makes debugging harder.

It would be nice if pgjdbc could just add SQL text.

Note: SQL text and bind variables might impose a security risk (e.g. SQL exceptions might be displayed to the end-user by mistake), so the feature should probably be disabled by default.