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

issues with backend-specific profiling should be limited
to tests that are explcitly against resultset, compiler, etc.

MySQL in particular has an often varying callcount that isn't
worth running these tests against nor is it worth profiling
them for other backends like Oracle and SQL Server.

Also add the REQUIRE_SQLALCHEMY_CEXT flag to
the regen_callcounts.tox.ini script, which is part of some review
somewhere but is needed here to generate callcounts correctly.

Add a "warmup" phase for some of the ORM tests for join conditions
that have varying profile counts based on whether mappings have been
used already or not; profiling should always be against the
"warmed up" version of a function.

Change-Id: If483820235fa4cc4360cbd067a9b68d83512d587

Removed all dialect code related to support for Jython and zxJDBC. Jython
has not been supported by SQLAlchemy for many years and it is not expected
that the current zxJDBC code is at all functional; for the moment it just
takes up space and adds confusion by showing up in documentation. At the
moment, it appears that Jython has achieved Python 2.7 support in its
releases but not Python 3.   If Jython were to be supported again, the form
it should take is against the Python 3 version of Jython, and the various
zxJDBC stubs for various backends should be implemented as a third party
dialect.

Additionally modernized logic that distinguishes between "cpython"
and "pypy" to instead look at platform.python_distribution() which
reliably tells us if we are cPython or not; all booleans which
previously checked for pypy and sometimes jython are now converted
to be "not cpython", this impacts the test suite for tests that are
cPython centric.

Fixes: #5094
Change-Id: I226cb55827f997daf6b4f4a755c18e7f4eb8d9ad

The C extensions have been broken since cc718cccc0bf8a01abdf4068c
however CI did not find this, because the build degraded to
non-C extensions without failing.   Ensure that if cext is set,
there is no fallback to non-cext build if the C extension build
fails.

Repair C related issues introduced in cc718cccc0bf8a01abdf4068c.

As C extensions have been silently failing on 2.7 for some commits,
the callcounts also needed to be adjusted for recent performance-related
changes.  That in turn required a fix to the profiling decorator
to use signature rewriting in order to support py.test's
fixture mechanism under Python 2, usage introduced under profiling
in 89bf6d80a9.

Fixes: #5076
Change-Id: Id968f10c85d6bf489298b1c318a1f869ad3e7d80

Change-Id: I08440dc25e40ea1ccea1778f6ee9e28a00808235

Identified a performance issue in the system by which a join is constructed
based on a mapped relationship.   The clause adaption system would be used
for the majority of join expressions including in the common case where no
adaptation is needed.   The conditions under which this adaptation occur
have been refined so that average non-aliased joins along a simple
relationship without a "secondary" table use about 70% less function calls.

Change-Id: Ifbe04214576e5a9fac86ca80c1dc7145c27cd50a

I use the nfl sort a lot to see what calling changes are happening
between two versions in order to identify the offending code, so
add it as a command line option.

Change-Id: Ia1ab6dd98012a78298b325bb5c7c050fa9b767c2

support that we have pytest-xdist arguments now,
as well as allow force-write to reset the list of callcounts which
seem to accumulate commas for some reason

Change-Id: I54dd164c21ffbb9139937d5c3ffb1df7e9598594

Change-Id: I6a71f4924d046cf306961c58dffccf21e9c03911

Applied on top of a pure run of black -l 79 in
I7eda77fed3d8e73df84b3651fd6cfcfe858d4dc9,  this set of changes
resolves all remaining flake8 conditions for those codes
we have enabled in setup.cfg.

Included are resolutions for all remaining flake8 issues
including shadowed builtins, long lines, import order, unused
imports, duplicate imports, and docstring issues.

Change-Id: I4f72d3ba1380dd601610ff80b8fb06a2aff8b0fe