Fix camelize_classname and pluralize_collection functions as they didn't work as expected.

feature would cause an object's version counter to be incremented
when there was no net change to the object's row, but instead an object
related to it via relationship (e.g. typically many-to-one)
were associated or de-associated with it, resulting in an UPDATE
statement that updates the object's version counter and nothing else.
In the use case where the relatively recent "server side" and/or
"programmatic/conditional" version counter feature were used
(e.g. setting version_id_generator to False), the bug could cause an
UPDATE without a valid SET clause to be emitted.
fixes #3465

an INSERT of NULL + pyodbc; pyodbc requires a special
object be passed in order to persist NULL.  As the :class:`.VARBINARY`
type is now usually the default for :class:`.LargeBinary` due to
:ticket:`3039`, this issue is partially a regression in 1.0.
The pymssql driver appears to be unaffected.
fixes #3464

JSONB support once again, as they suddenly
switched on unconditional decoding of JSONB types in version 2.7.1.
Version detection now specifies 2.7.1 as where we should expect
the DBAPI to do json encoding for us.
fixes #3439

as we are using db_opts for the first time with legacy_schema_args

- changelog
- versionadded + reflink for new pg storage parameters doc
- pep8ing
- add additional tests to definitely check that the Index object
is created all the way with the opts we want
fixes #3455