assisting with alembic installations that have upgraded and are dealing with
PG index/unique constraint reflection.

Inspection API already supports reflection of table
indexes information and those also include unique
constraints (at least for PostgreSQL and MySQL).
But it could be actually useful to distinguish between
indexes and plain unique constraints (though both are
implemented in the same way internally in RDBMS).

This change adds a new method to Inspection API - get_unique_constraints()
and implements it for SQLite, PostgreSQL and MySQL dialects.

when using the pypostgresql adapter, which returns these values
as lists vs. psycopg2's return type of string.
[ticket:2855]

Conflicts:
	doc/build/changelog/changelog_09.rst
	lib/sqlalchemy/__init__.py

server default for a column; this code was original from
PG system views which truncated the string for readability.
[ticket:2844]

rendered in the column list of a CREATE INDEX statement.
[ticket:2742]

mssql to ensure that any literal SQL expression values are
rendered directly as literals, instead of as bound parameters,
within a CREATE INDEX statement. [ticket:2742]
- don't need expression_as_ddl(); literal_binds and include_table
take care of this functionality.

Conflicts:
	lib/sqlalchemy/sql/util.py

- use match with a .* preceding instead of search

re.match to re.search

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]

Conflicts:
	doc/build/changelog/changelog_09.rst

backslashed quotes would not be escaped correctly when
using the "non native" (i.e. non-psycopg2) means
of translating HSTORE data.  Patch courtesy Ryan Kelly.
[ticket:2766]

Conflicts:
	doc/build/changelog/changelog_09.rst
	lib/sqlalchemy/dialects/postgresql/hstore.py