Add --encoding to pg_dump.

The Problem:  Occassionally a DBA needs to dump a database to a new
encoding.   In instances where the current encoding, (or lack of an
encoding, like SQL_ASCII) is poorly supported on the target  database
server, it can be useful to dump into a particular  encoding.  But,
currently the only way to set the encoding of  a pg_dump file is to
change  client_encoding in postgresql.conf and restart postmaster.
This is more  than a little awkward for production systems.

Magnus Hagander