2. compiler names changed to be less verbose, unused classes removed.
3. Methods on Dialect which return compilers, schema generators, identifier preparers
have changed to direct class references, typically on the Dialect class itself
or optionally as attributes on an individual Dialect instance if conditional behavior is needed.
This takes away the need for Dialect subclasses to know how to instantiate these
objects, and also reduces method overhead by one call for each one.
4. as a result of 3., some internal signatures have changed for things like compiler() (now statement_compiler()), preparer(), etc., mostly in that the dialect needs to be passed explicitly as the first argument (since they are just class references now).  The compiler() method on Engine and Connection is now also named statement_compiler(), but as before does not take the dialect as an argument.

5. changed _process_row function on RowProxy to be a class reference, cuts out 50K method calls from insertspeed.py

  SQL expressions to be pickleable [ticket:735]

- small adjustment to mapper class.__init__ to allow for Py2.6 object.__init__()
  behavior

of convert_bind_param() and convert_result_value() to callable-returning
bind_processor() and result_processor() methods.  if no callable is
returned, no pre/post processing function is called.
- hooks added throughout base/sql/defaults to optimize the calling
of bind param/result processors so that method call overhead is minimized.
special cases added for executemany() scenarios such that unneeded "last row id"
logic doesn't kick in, parameters aren't excessively traversed.
- new performance tests show a combined mass-insert/mass-select test as having 68%
fewer function calls than the same test run against 0.3.
- general performance improvement of result set iteration is around 10-20%.

- marked as unsupported for mssql all two-phase and nested transcation tests
- marked as unsupported for mssql various transactional/session tests which require two connections looking at uncommitted/external data at the same time (ms-sql cant handle it)
- put better explicit closeout step in unitofwork.py tests to appease ms-sqls hard locking

- has_key()->__contains__()

all are merged into a single stack thats all within ansicompiler.  clause visiting cut down
significantly.

    checking this state added a lot of method call overhead and there was
    no decent reason to ever set it to False.  Table and column names which are
    all lower case will be treated as case-insenstive (yes we adjust for
    Oracle's UPPERCASE style too).