Allow a custom query class in ShardedSession so it can be defined by sessionmaker

[Former user]

Make the query class customizable on ShardedSession to allow something like this:

class ShardedCachingQuery(CachingQuery, ShardedQuery):
    pass

Session = scoped_session(
                sessionmaker(
                    class_=ShardedSession,
                    query_cls=caching_query.query_callable(cache_manager,ShardedCachingQuery)

[Mike Bayer]

the patch was not quite it, needed constructor fix, reordering of the two classes, different patch for 0.6 versus 0.7.

ff1868b3f045435e3829eefa6d6911f492569dca 85e0054d677f17cc9c9a9f84d957cc7c0be0a6c5

[Mike Bayer]

Removing milestone: 0.6.7 (automated comment)