Add `postgresql_psycopg2binary` install extra that installs `psycopg2-binary`
Add `postgresql_psycopg2binary` install extra that installs `psycopg2-binary`

Fixes: #4306
Change-Id: I26edc1a4ac8a7f9f3f258bb03009ebfa4cc00e1a
Pull-request: https://github.com/zzzeek/sqlalchemy/pull/465

graingert/sqlalchemy,j5int/sqlalchemy,wujuguang/sqlalchemy,wujuguang/sqlalchemy,monetate/sqlalchemy,sqlalchemy/sqlalchemy,graingert/sqlalchemy,monetate/sqlalchemy,j5int/sqlalchemy,zzzeek/sqlalchemy