notnull: false is ignored for integers with the mssql export

The following yml schema will result in a table with the integer field marked as not null

MyTable:
columns:
intfield:
type: integer
notnull: false

I have traced this back to line 244 in the getIntegerDeclaration function in lib/Doctrine/DataDict/Mssql.php

$notnull = (isset($field['notnull']) && $field['notnull']) ? ' NOT NULL' : '';

should be

$notnull = (isset($field['notnull']) && $field['notnull']) ? ' NOT NULL' : ' NULL';

This fixes the issue for us and hasn't created any problems thus far.