Bug 135192 [Regression] Maximum number of rows in data set preview doesn't work for script data source.
Description: Maximum number of rows in data set preview doesn't work for script data source. Steps to reproduce: 1. Create a script data source and create a related data set. 2. Set maximum number of rows in preferences. Expected result: it works as setting. Actual result: maximum number of rows setting doesn't take effect.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/preferences/DateSetPreferencePage.java
*  This class represents a preference page that is contributed to the
 * 	Preferences dialog.
 * 	This page is used to modify dataset preview preferences only. They are stored 
 *  in the preference store that belongs to the main plug-in class. 
 *  That way, preferences can be accessed directly via the preference store.
 */
public class DateSetPreferencePage extends PreferencePage
		implements IWorkbenchPreferencePage
{
	private IntegerFieldEditor maxRowEditor;
	private IntegerFieldEditor maxDisplaySchemaEditor;
	private IntegerFieldEditor maxDisplayTableEditor;
	
	
	public static final int DEFAULT_MAX_ROW = 500;
	
	
	public static final int DEFAULT_MAX_NUM_OF_SCHEMA = 20;
	
	
	public static final int DEFAULT_MAX_NUM_OF_TABLE_EACH_SCHEMA = 100;
	
	private static final int MAX_MAX_ROW = Integer.MAX_VALUE;
	
	
	public static final String USER_MAXROW = "user_maxrow"; 
	public static final String USER_MAX_NUM_OF_SCHEMA = "user_max_num_of_schema";
	public static final String USER_MAX_NUM_OF_TABLE_EACH_SCHEMA="user_max_num_of_table_each_schema";
	/*
	 * @see org.eclipse.jface.preference.PreferencePage#createContents(org.eclipse.swt.widgets.Composite)