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 FORMAT_TYPE_EMAIL = "email"; 
	public static final String FORMAT_TYPE_PRINT = "print"; 
	public static final String FORMAT_TYPE_PDF = "pdf"; 
	public static final String FORMAT_TYPE_RTF = "rtf"; 
	public static final String FORMAT_TYPE_REPORTLET = "reportlet"; 
	public static final String FORMAT_TYPE_EXCEL = "excel"; 
	public static final String FORMAT_TYPE_WORD = "word"; 
	public static final String FORMAT_TYPE_POWERPOINT = "powerpoint"; 	
	public static final String FORMAT_TYPE_DOC = "doc"; 
	/**
	 * ImageRefType -- The image reference type. The first constant is the name
	 * of ImageRefType choice. The followed constants are valid choice values of
	 * ImageRefType.
	 */
	public static final String CHOICE_IMAGE_REF_TYPE = "imageRefType"; 
	public static final String IMAGE_REF_TYPE_NONE = "none"; 
	public static final String IMAGE_REF_TYPE_FILE = "file"; 
	public static final String IMAGE_REF_TYPE_URL = "url"; 
	public static final String IMAGE_REF_TYPE_EXPR = "expr"; 
	public static final String IMAGE_REF_TYPE_EMBED = "embed"; 
	/**
	 * propertyMaskType -- The choice for the property mask. The first constant
	 * is the name of propertyMaskType choice. The followed constants are valid
	 * choice values of propertyMaskType.
	 */
	public static final String CHOICE_PROPERTY_MASK_TYPE = "propertyMaskType"; 
	public static final String PROPERTY_MASK_TYPE_CHANGE = "change"; 
	public static final String PROPERTY_MASK_TYPE_LOCK = "lock"; 
	public static final String PROPERTY_MASK_TYPE_HIDE = "hide"; 
	/**