Bug 153896 Improve the performance of BIRT datetime-converting
The current datetime converting algorithm in birt.core, xml&flatfile ODA implementations are not efficient enough.This is because we use java's SimpleDateTimeFormatter to parse ISO8601 compatible date/time values. We should write our own datatime string parser for ISO8601 datetime format.
core/org.eclipse.birt.core/src/org/eclipse/birt/core/data/DataTypeUtil.java
* @throws BirtException
	 */
	public static String toString( Object source, Locale locale )
			throws BirtException
	{
		return toString( source, ULocale.forLocale( locale ) );
	}
	/**
	 * Number -> String
	 * 		Number.toString()
	 * Boolean -> String
	 * 		Boolean.toString()
	 * Date	-> String
	 * 		toString(Date,locale)
	 * @param source
	 * @return
	 * @throws BirtException
	 */
	public static String toString( Object source, ULocale locale )
			throws BirtException
	{
		if ( source == null )
			return null;
		if ( source instanceof Date )
		{
			return toString( (Date) source, locale );
		}
		else
		{
			String str = "";