consists mainly of adjusting fixtures to ensure connections are closed
explicitly.  psycopg2cffi also handles unicode bind parameter
names differently than psycopg2, and seems to possibly have a little less
control over floating point values at least in one test which is
marked as a "fail", though will see if it runs differently on linux
than osx..
- changelog for psycopg2cffi, fixes #3052

return type is not strictly assumed to be boolean; it now
returns a :class:`.Boolean` subclass called :class:`.MatchType`.
The type will still produce boolean behavior when used in Python
expressions, however the dialect can override its behavior at
result time.  In the case of MySQL, while the MATCH operator
is typically used in a boolean context within an expression,
if one actually queries for the value of a match expression, a
floating point value is returned; this value is not compatible
with SQLAlchemy's C-based boolean processor, so MySQL's result-set
behavior now follows that of the :class:`.Float` type.
A new operator object ``notmatch_op`` is also added to better allow
dialects to define the negation of a match operation.
fixes #3263

- add __backend__ to most tests so that pg8000 can start coming in

Found using: https://github.com/intgr/topy

(pre 8.1) versions of Postgresql, and potentially other PG engines
such as Redshift (assuming Redshift reports the version as < 8.1).
The query for "indexes" as well as "primary keys" relies upon inspecting
a so-called "int2vector" datatype, which refuses to coerce to an array
prior to 8.1 causing failures regarding the "ANY()" operator used
in the query.  Extensive googling has located the very hacky, but
recommended-by-PG-core-developer query to use when PG version < 8.1
is in use, so index and primary key constraint reflection now work
on these versions.

Postgresql dialect to no longer inject a hardcoded ``::timestamp``
or similar cast into the given expression, as this interfered
with types such as timezone-aware datetimes, but also
does not appear to be at all necessary with modern versions
of psycopg2.  Also in 0.8.2.
[ticket:2740]