Bug 179674 Support time dimension in model
When define time dimension in model, the "itTime" property will be set. However this is not enough. We also need to know to what precision the time value should be evaluated, say, year, month, day, etc. Model needs to be enhanced to support such requirement.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/olap/LevelHandle.java
setStringProperty( LEVEL_TYPE_PROP, levelType );
	}
	/**
	 * Returns the data type of this level. The possible values are defined in
	 * {@link org.eclipse.birt.report.model.api.elements.DesignChoiceConstants},
	 * and they are:
	 * <ul>
	 * <li>COLUMN_DATA_TYPE_ANY
	 * <li>COLUMN_DATA_TYPE_INTEGER
	 * <li>COLUMN_DATA_TYPE_STRING
	 * <li>COLUMN_DATA_TYPE_DATETIME
	 * <li>COLUMN_DATA_TYPE_DECIMAL
	 * <li>COLUMN_DATA_TYPE_FLOAT
	 * <li>COLUMN_DATA_TYPE_STRUCTURE
	 * <li>COLUMN_DATA_TYPE_TABLE
	 * </ul>
	 * 
	 * @return the data type of this level.
	 */
	public String getDataType( )
	{
		return getStringProperty( DATA_TYPE_PROP );
	}
	/**
	 * Sets the data type of this level. The allowed values are defined in
	 * {@link org.eclipse.birt.report.model.api.elements.DesignChoiceConstants},
	 * and they are:
	 * <ul>
	 * <li>COLUMN_DATA_TYPE_ANY
	 * <li>COLUMN_DATA_TYPE_INTEGER