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/elements/DesignChoiceConstants.java
public static final String TARGET_NAMES_TYPE_TOP = "_top"; 
	/**
	 * templateElementType -- the template element type The first constant is
	 * the name of the templateElementType choice set. The followed constants
	 * are valid choice values of the templateElementType.
	 */
	public static final String CHOICE_TEMPLATE_ELEMENT_TYPE = "templateElementType"; 
	public static final String TEMPLATE_ELEMENT_TYPE_TABLE = "Table"; 
	public static final String TEMPLATE_ELEMENT_TYPE_FREEFORM = "FreeForm"; 
	public static final String TEMPLATE_ELEMENT_TYPE_DATA = "Data"; 
	public static final String TEMPLATE_ELEMENT_TYPE_GRID = "Grid"; 
	public static final String TEMPLATE_ELEMENT_TYPE_IMAGE = "Image"; 
	public static final String TEMPLATE_ELEMENT_TYPE_LABEL = "Label"; 
	public static final String TEMPLATE_ELEMENT_TYPE_LIST = "List"; 
	public static final String TEMPLATE_ELEMENT_TYPE_TEXT = "Text"; 
	public static final String TEMPLATE_ELEMENT_TYPE_EXTENDED_ITEM = "ExtendedItem"; 
	public static final String TEMPLATE_ELEMENT_TYPE_TEXT_DATA = "TextData"; 
	public static final String TEMPLATE_ELEMENT_TYPE_DATA_SET = "DataSet"; 
	/**
	 * sortType -- the sort type. The first constant is the name of the sortType
	 * choice set. The followed constants are valid choice values of the
	 * sortType.
	 */
	public static final String CHOICE_SORT_TYPE = "sortType"; 
	public static final String SORT_TYPE_NONE = "none"; 
	public static final String SORT_TYPE_SORT_ON_GROUP_KEY = "sort-on-group-key"; 
	public static final String SORT_TYPE_COMPLEX_SORT = "complex-sort"; 
	/**
	 * joinType -- join type of join condition.
	 */