into(sql, *) with better datetime support

changes and tests to support into(sql, *) where the source is
a pd.DataFrame, numpy array or dynd array, bcolz.ctable

If the source has a datetime with a timezone, make use of
sqlalchemy DateTime with timezone support

This also helps with operations of the form into(*, sql) where
the sql table has datetimes with time zone
simplify into(np.ndarray, Iterable)

exclude into(sql, mongoDB.Collection)
into(ctable, (list, tuple)) takes names kwarg
small fixes for into(sql, *)

- typo in Tables exception
- adds into(sql, mongoDB collection)
- only enforce datetime tz when adding to empty SQL db
sql: more robust datetime timezone handling
Merge branch 'into_sql'