QSqlTableModel::removeRows(): require valid full range of rows

QSqlTableModel::removeRows(): require valid full range of rows

If an invalid range of rows is specified, it's likely to be a
programming or user error. The old behavior of ignoring out of range
rows seems dangerous and complicates the code.

Also implement the documented behavior of returning false if
changes are unsuccessful for OnFieldChange and OnRowChange.
Previously the return value of submit() was ignored.

Updated and improved documentation.

Change-Id: Iaaf51c6d9a0c8c06fd5d186b4b88358fbeab9936
Reviewed-by: Yunqiao Yin <charles.yin@nokia.com>