oriented row lookups were not matching up to the ad-hoc :class:`.ColumnClause`
objects that :class:`.TextAsFrom` generates, thereby making it not
usable as a target in :meth:`.Query.from_statement`.  Also fixed
:meth:`.Query.from_statement` mechanics to not mistake a :class:`.TextAsFrom`
for a :class:`.Select` construct.  This bug is also an 0.9 regression
as the :meth:`.Text.columns` method is called to accommodate the
:paramref:`.text.typemap` argument. [ticket:2932]

:class:`.Query` and in other situations where selects or joins
were aliased (such as joined table inheritance) could fail if a
user-defined :class:`.Column` subclass were used in the expression.
In this case, the subclass would fail to propagate ORM-specific
"annotations" along needed by the adaptation.  The "expression
annotations" system has been corrected to account for this case.
[ticket:2918]

alias when saying query(B).join(B.cs), where "C" is a joined inh
class; however, this implicit alias was created only considering
the immediate left side, and not a longer chain of joins along different
joined-inh subclasses of the same base.   As long as we're still
implicitly aliasing in this case, the behavior is dialed back a bit
so that it will alias the right side in a wider variety of cases.
[ticket:2903]

- implement Query with_for_update()
- rework docs and tests

- move out tests, dialect specific out of compiler, compiler tests use new API,
legacy API tests in test_selecatble
- add support for adaptation of ForUpdateArg, alias support in compilers