Fixed two date/time related bugs in Sqlserver

1. I've encountered this at least 3/4 year old bug:
http://ask.cakephp.org/por/questions/view/created_and_modified_fields_with_sql_server

The mentioned fix helped me.
I used CakePHP 2.3.1 with MS SQL 2008.

2. Also fixed the timestamp data type.
MSSQL's timestamp isn't the same as MySQL's:
MSSQL = http://msdn.microsoft.com/en-us/library/aa260631%28v=sql.80%29.aspx
MySQL = http://dev.mysql.com/doc/refman/5.1/de/timestamp-4-1.html

Also the following line should probably be swapped, too.
From:
'date' => array('name' => 'datetime', 'format' => 'Y-m-d', 'formatter' => 'date'),
To:
'date' => array('name' => 'datetime', 'format' => 'Ymd', 'formatter' => 'date'),