Changes in 1.2 (19 Apr 2011):
 * Replace atoi(), New methods (column_uint, column_uint64). (fa1f650)
 * Use atomic op to increment or decrement instance_count_. (1bdeda8)

Changes in 1.1 (07 Feb 2011):
 * Add error methods. (87599be)
 * Update sample code to use error methods. (ee367f6)
 * Add row_count method. (4910ee7)
 * Add get_affected_rows method. (f23e772)
 * Add note about the index argument. (f8cd1bf)