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
* @return
	 * @throws BirtException
	 */
	public static Integer toInteger( Object source ) throws BirtException
	{
		if ( source == null )
			return null;
		if ( source instanceof Integer )
		{
			return (Integer) source;
		}
		else if ( source instanceof Number )
		{
			 
			
			int intValue = ( (Number) source ).intValue( );
			return new Integer( intValue );
		}
		else if ( source instanceof Boolean )
		{
			if ( true == ( (Boolean) source ).booleanValue( ) )
				return new Integer( 1 );
			return new Integer( 0 );
		}
		else if ( source instanceof Date )
		{
			long longValue = ( (Date) source ).getTime( );
			return new Integer( (int) longValue );
		}
		else if ( source instanceof String )