base

Fix SQLite limit issue.

SQLLite limit is not only used to limit the returned number of data.
It can be used to do an offset query.

For example, "SELECT * FROM table LIMIT 100, 10", will return the
data of index in the range of [100, 100 + 10).

This change set enable this kind of useage.

This is also more efficient than use "cursor.moveToPosition()".
In my experiment, I query 1000 items in batch mode, i.e.,
get 20 items out of 1000 each time.

    Time of using LIMIT clause: 626ms
    Time of useing "cursor.moveToPosition()": 2062ms