Add `sqlalchemy.ext.index.index_property`
which subscribe an index of a column with `Indexable` type.

Co-authored-by: Mike Bayer <mike_mp@zzzcomputing.com>
Change-Id: I238c23131e4fded5dc7f7a25eb02e26008099d00
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/235

This allows automap to reflect tables from a schema other than the
default without the need to resort to calling MetaData.reflect
directly.

Change-Id: Ie73cb113bd6d115555c09c5efc33d27ad2c9c512
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/237

As per their email ‘Changes to project subdomains’:

> Starting today, Read the Docs will start hosting projects from subdomains on the domain readthedocs.io, instead of on readthedocs.org. This change addresses some security concerns around site cookies while hosting user generated data on the same domain as our dashboard.

Test Plan: Manually visited all the links I’ve modified.

Keystone and others depend on the .property attribute being
"mirrored" when a @hybrid_property is linked directly to a
mapped attribute.  Restore this linkage and also create a defined
behavior for the .info dictionary; it is that of the hybrid itself.
Add this behavioral change to the migration notes.

Change-Id: I8ac34ef52039387230c648866c5ca15d381f7fee
References: #3653

The docstring specified on a hybrid property or method is now honored
at the class level, allowing it to work with tools like Sphinx
autodoc.  The mechanics here necessarily involve some wrapping of
expressions to occur for hybrid properties, which may cause them
to appear differently using introspection.

Fixes: #3653
Change-Id: I02549977fe8b2a051802eed7b00cc532fbc214e3
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/239

to the new MutableList and MutableSet classes, fixes #3297

from https://bitbucket.org/zzzeek/sqlalchemy/issues/3297