Txpostgres

------------------------------

- Python 3 compatibility, the test suite now passes in Python 3.4
and 3.5 using latest Twisted trunk

------------------------------

- notifications are not longer duplicated when obsrever functions
execute their own queries (thanks to Max Walton)

------------------------------

- internally used cursors are no longer explicitly closed, although
it should not cause any user-visible changes

------------------------------

- try using psycopg2cffi before falling back to psycopg2-ctypes
(while still prefering straingh psycopg2)
- allow choosing the exact psycopg2 implementation using an
environment variable
- NOTIFY events are now processed in reception order (thanks to
Max Walton)
- tests are more robust and adapted to work on recent
Postgres versions
- cursors provided in runInteraction are now always closed
automatically (thanks to Willi Schinmeyer)

------------------------------

- support for simple automatic reconnection

------------------------------

- Sphinx documentation and examples were added in an attempt to
produce some formal docs and guide for new txpostgres users

- NOTIFY events are now processed using a Cooperator to avoid
blocking the reactor thread in case there are many