Added an adapter for None: it is usually not invoked as adaptation to
NULL is a fast path in mogrify, but can be invoked by composite types.
Notice that composite types still have the option to fast-path None
(e.g. list adapter does).
This cuts off server whose version is older than 7.4. But enables us to
remove large portions of code rarely used and tested (e.g. p2 copy) and
will allow us to drop the query we do at each connection to establish
the client encoding and the datestyle.
* Merged NEWS-2.3 and NEWS-2.2: 2.0 (pre-async) still makes sense in case
someone has horrible problems with the new code but 2.3 will just
substitute 2.2 so having a separated NEWS file doesn't make sense.
* Moved authors and contributors to AUHTORS file.
* README now has pointers to web site and bug tracker.
* Updated MonoDevelop project.
