webdb: Moved code common to Where and Table into new base class Selectable
webdb: DB.__enter__ and .__exit__ point to __driver__ methods
doctest/drivers/runsuite.py: Added test for Selection.get
webdb: Shortened Table._by_pk helper for __getitem__
webdb: Removed Selection.__contains__

x in table.select() should be done in db using (table.a == a).select()
webdb: Changed Selection iteration to only allow one pass over the result set
webdb: Added sql syntax error handling
doctest/drivers: runsuite is now a module for other driver-specific test suites
webdb: Implemented Selection.__nonzero__
doctest/drivers/runsuite.py: Removed unnecessary imports
webdb: Selection.one calls next directly
webdb: Added more Selection member access methods
doctest/drivers/runsuite.py: filters options for underscores later
doctest/drivers: Added verbosity argument to driver tests
Removed doctest/testwebdbdrivers.py