The docstrings for connect() and on_connect() were incorrect
between Dialect vs. DefaultDialect.   Redocumented related
methods, clean up formatting, and remove unicode-related
attribute descriptions from the top level Dialect document
as these don't apply to Python 3.

Change-Id: I45baab757f8e20627eba42c30b9e8dbe26356275

This builds on cc718cccc0bf8a01abdf4068c7ea4f3 which moved
RowProxy to Row, allowing Row to be more like a named tuple.

- KeyedTuple in ORM is replaced with Row

- ResultSetMetaData broken out into "simple" and "cursor" versions
  for ORM and Core, as well as LegacyCursor version.

- Row now has _mapping attribute that supplies full mapping behavior.
Row and SimpleRow both have named tuple behavior otherwise.
LegacyRow has some mapping features on the tuple which emit
deprecation warnings (e.g. keys(), values(), etc).   the biggest
change for mapping->tuple is the behavior of __contains__ which
moves from testing of "key in row" to "value in row".

- ResultProxy breaks into ResultProxy and FutureResult (interim),
the latter has the newer APIs.   Made available to dialects
using execution options.

- internal reflection methods and most tests move off of implicit
Row mapping behavior and move to row._mapping, result.mappings()
method using future result

- a new strategy system for cursor handling replaces the various
subclasses of RowProxy

- some execution context adjustments. We will leave EC in but
refined things like get_result_proxy() and out parameter handling.
Dialects for 1.4 will need to adjust from get_result_proxy()
to get_result_cursor_strategy(), if they are using this method

- out parameter handling now accommodated by get_out_parameter_values()
EC method.   Oracle changes for this.  external dialect for
DB2 for example will also need to adjust for this.

- deprecate case_insensitive flag for engine / result, this
feature is not used

mapping-methods on Row are deprecated, and replaced with
Row._mapping.<meth>, including:

   row.keys()  -> use row._mapping.keys()
   row.items()  -> use row._mapping.items()
   row.values() -> use row._mapping.values()
   key in row  -> use key in row._mapping
   int in row  -> use int < len(row)

Fixes: #4710
Fixes: #4878
Change-Id: Ieb9085e9bcff564359095b754da9ae0af55679f0

The :meth:`.Connection.connect` method is deprecated as is the concept of
"connection branching", which copies a :class:`.Connection` into a new one
that has a no-op ".close()" method.  This pattern is oriented around the
"connectionless execution" concept which is also being removed in 2.0.

As part of this change we begin to move the internals away from
"connectionless execution" overall.   Remove the "connectionless
execution" concept from the reflection internals and replace with
explicit patterns at the Inspector level.

Fixes: #5131
Change-Id: Id23d28a9889212ac5ae7329b85136157815d3e6f

Change-Id: I08440dc25e40ea1ccea1778f6ee9e28a00808235

The :meth:`.Index.create` and :meth:`.Index.drop` methods now have a
parameter :paramref:`.Index.create.checkfirst`, in the same way as that of
:class:`.Table` and :class:`.Sequence`, which when enabled will cause the
operation to detect if the index exists (or not) before performing a create
or drop operation.

Fixes: #527
Change-Id: Idf994bc016359d0ae86cc64ccb20378115cb66d6

- Deprecated remaining engine-level introspection and utility methods
including :meth:`.Engine.run_callable`, :meth:`.Engine.transaction`,
:meth:`.Engine.table_names`, :meth:`.Engine.has_table`.   The utility
methods are superseded by modern context-manager patterns, and the table
introspection tasks are suited by the :class:`.Inspector` object.

- The internal dialect method ``Dialect.reflecttable`` has been removed.  A
review of third party dialects has not found any making use of this method,
as it was already documented as one that should not be used by external
dialects.  Additionally, the private ``Engine._run_visitor`` method
is also removed.

- The long-deprecated ``Inspector.get_table_names.order_by`` parameter has
been removed.

- The :paramref:`.Table.autoload_with` parameter now accepts an :class:`.Inspector` object
directly, as well as any :class:`.Engine` or :class:`.Connection` as was the case before.

Fixes: #4755
Change-Id: Iec3a8b0f3e298ba87d532b16fac1e1132f464e21

The "threadlocal" execution strategy, deprecated in 1.3, has been
removed for 1.4, as well as the concept of "engine strategies" and the
``Engine.contextual_connect`` method.  The "strategy='mock'" keyword
argument is still accepted for now with a deprecation warning; use
:func:`.create_mock_engine` instead for this use case.

Fixes: #4632
Change-Id: I8a351f9fa1f7dfa2a56eec1cd2d1a4b9d65765a2
(cherry picked from commit b368c49b44c5716d93c7428ab22b6761c6ca7cf5)

Fixed bug where using reflection function such as :meth:`.MetaData.reflect`
with an :class:`.Engine` object that had execution options applied to it
would fail, as the resulting :class:`.OptionEngine` proxy object failed to
include a ``.engine`` attribute used within the reflection routines.

Fixes: #4754
Change-Id: I6c342af5c6db6fe362b9d25f3f26d6859f62f87a

Added new parameters :paramref:`.Table.resolve_fks` and
:paramref:`.MetaData.reflect.resolve_fks` which when set to False will
disable the automatic reflection of related tables encountered in
:class:`.ForeignKey` objects, which can both reduce SQL overhead for omitted
tables as well as avoid tables that can't be reflected for database-specific
reasons.  Two :class:`.Table` objects present in the same :class:`.MetaData`
collection can still refer to each other even if the reflection of the two
tables occurred separately.

Fixes: #4517
Change-Id: I623baed42042a16c5109e4c8af6b2f64d2d00f95

This affects mostly docstrings, except in orm/events.py::dispose_collection()
where one parameter gets renamed: given that the method is
empty, it seemed reasonable to me to fix that too.

Closes: #4440
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/4440
Pull-request-sha: 779ed75acb6142e1f1daac467b5b14134529bb4b

Change-Id: Ic0553fe97853054b09c2453af76d96363de6eb0e