The attributeimpl for a deferred_expression does not
support a scalar loader, add new configurability so that
the impl can have this flag turned off.   Document
that the with_expression() system currently does not
offer any deferred loading.

To eliminate confusion over "deferred", which refers to
lazy loading of column attributes, and "with_expression",
which refers to an attribute that is explicitly at
query time only, rename deferred_expression to query_expression.

Change-Id: I07c4a050ed68c79ccbde9492e9de1630b7470d74

Change-Id: I4e8c2aa8fe817bb2af8707410fa0201f938781de

Options like uselist and backref can be determined from
within _register_attribute based on parent_property
given; move this logic inside so that individual strategies
have less responsibility.  Also don't require that
_register_attribute consider the "strategy" itself
at all; it would be better if we could no longer require
that Joined/Subquery/etc loaders call upon the "lazy" strategy
in order to initialize attribute instrumentation and
this could be done more generically.

Fixes long-standing bug where the "noload" relationship loading
strategy would cause backrefs and/or back_populates options to be
ignored.   There is concern that some application that uses
"noload" might be surprised at a back-populating attribute
appearing suddenly, which may have side effects.  However,
"noload" itself must be extremely seldom used since as a
strategy, it already disables loading, population of attributes
is the only behavior that is even supported, so that this issue has existed
for at least through 0.7 four years ago without ever being
reported indicates extremely low use of this option.

Change-Id: Icffb9c83ac5782b76ce882ed1df4361a1efbfba3
Fixes: #3845

Includes removal of adapt_like_to_iterable() as well
as _set_iterable(), uses __slots__ for collectionadapter,
does much less duck typing of collections.

- prop.compare() isn't needed; replace with prop._with_parent()
for relationships
- update docs in orm/interfaces

sqlalchemy/orm, sqlalchemy/event, sqlalchemy/testing

to get all flake8 passing

of :ticket:`3060` from verision 0.9.5.  A self-referential relationship
with lazy='dynamic' would raise a TypeError within a flush operation.
fixes #3099