would fail if the underlying table (but not the actual alias)
were referenced inside the subquery generated by
q.from_self() or q.select_from().

or similar complex expression on a single-table inheritance
relation(). [ticket:1731]

passed to the resulting statement. Currently only
Select-statements have these options, and the only option
used is "stream_results", and the only dialect which knows
"stream_results" is psycopg2.
- Query.yield_per() will set the "stream_results" statement
option automatically.
- Added "statement_options()" to Selects, which set statement
specific options. These enable e.g. dialect specific options
such as whether to enable using server side cursors, etc.
- The psycopg2 now respects the statement option
"stream_results". This option overrides the connection setting
"server_side_cursors". If true, server side cursors will be
used for the statement. If false, they will not be used, even
if "server_side_cursors" is true on the
connection. [ticket:1619]
- added a "frozendict" from http://code.activestate.com/recipes/414283/,
adding more default collections as immutable class vars on
Query, Insert, Select

cloned or adapted (occurs frequently in ORM operations).
[ticket:1641]

adds a __nonzero__ to _BinaryExpression to avoid faulty comparisons during hash
collisions (which only occur on Jython)
fixes #1547

the string "field" argument was getting treated as a
ClauseElement, causing various errors within more
complex SQL transformations.