What's new in psycopg 2.3
-------------------------

Psycopg 2.3 aims to expose some of the new features introduced in PostgreSQL
9.0.

* New features:

  - `dict` to `hstore` adapter and `hstore` to `dict` typecaster, using both
    9.0 and pre-9.0 syntax.
  - Two-phase commit protocol support as per DBAPI specification.
  - Support for payload in notifications received from the backed.

* Other changes:

  - `mogrify()` now supports unicode queries.
  - Dropped deprecated Psycopg "own quoting".
  - `errorcodes` knows a couple of new codes introduced in PostgreSQL 9.0.
  - Never issue a ROLLBACK on close/GC. This behaviour was introduced as a bug
    in release 2.2, but trying to send a command while being destroyed has been
    considered not safe.

* Bug fixes:

  - Fixed use of `PQfreemem` instead of `free` in binary typecaster.
  - Fixed access to freed memory in `conn_get_isolation_level()`.