query for  "show standard_conforming_strings"; as this variable was
added as of PG 8.2, we skip the query for PG versions older than
that as well as for backends like Redshift. #2946

reflection query were updated to take into account primary key constraints
that were renamed; the newer query fails on very old versions of
Postgresql such as version 7, so the old query is restored in those cases
when server_version_info < (8, 0) is detected. #2291

Closes #2934

pymysql) from working in Py3K, where a check for "connection
charset" would fail due to Py3K's more strict value comparison
rules.  The call in question  wasn't taking the database
version into account in any case as the server version was
still None at that point, so the method overall has been
simplified to rely upon connection.character_set_name().
[ticket:2933]

to support dialect-level reflection options for all :class:`.Table`
objects reflected.

- Added a new dialect-level argument ``postgresql_ignore_search_path``;
this argument is accepted by both the :class:`.Table` constructor
as well as by the :meth:`.MetaData.reflect` method.  When in use
against Postgresql, a foreign-key referenced table which specifies
a remote schema name will retain that schema name even if the name
is present in the ``search_path``; the default behavior since 0.7.3
has been that schemas present in ``search_path`` would not be copied
to reflected :class:`.ForeignKey` objects.  The documentation has been
updated to describe in detail the behavior of the ``pg_get_constraintdef()``
function and how the ``postgresql_ignore_search_path`` feature essentially
determines if we will honor the schema qualification reported by
this function or not. [ticket:2922]

such as "literal binds" into a CAST expression.
- Fixed bug whereby binary type would fail in some cases
if used with a "test" dialect, such as a DefaultDialect or other
dialect with no DBAPI.
- Fixed bug where "literal binds" wouldn't work with a bound parameter
that's a binary type.  A similar, but different, issue is fixed
in 0.8.

where a more specific type is adapted to a more generic one - this
use case is needed by some third party tools such as ``sqlacodegen``.
The specific cases that needed repair within this test suite were that
of :class:`.mysql.ENUM` being downcast into a :class:`.types.Enum`,
and that of SQLite date types being cast into generic date types.
The ``adapt()`` method needed to become more specific here to counteract
the removal of a "catch all" ``**kwargs`` collection on the base
:class:`.TypeEngine` class that was removed in 0.9. [ticket:2917]

- clean up some shenanigans in reflection