check sqlite connection for an existing date handler

[Mike Bayer]

i.e. if connected via:

       engine = create_engine('sqlite://',
                              echo='debug', 
                              encoding='utf-8',  
                              pool_recycle=3600,
                              connect_args={'detect_types': sqlite3.PARSE_DECLTYPES|sqlite3.PARSE_COLNAMES})

[Mike Bayer]

its alot uglier than that. Added a flag to get minimal support in 44626e96595f25f9580e45ffa930fdec0f1b07a8, but pysqlite's support here is a lot more spotty than what straight up SQLAlchemy gives you.

[Mike Bayer]

Removing milestone: 0.6.0 (automated comment)