Bug 195607 NPE is thrown when calling DimensionHandle:: getAbsoluteValue()
If a DimensionHandle did not set DimensionValue, NPE will thrown when calling DimensionHandle:: getAbsoluteValue().
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DimensionHandle.java
* 
	 * <p>
	 * CSS 2.1 specification has the following statements:
	 * <p>
	 * Child elements do not inherit the relative values specified for their
	 * parent; they inherit the computed values.
	 * <p>
	 * Example(s):
	 * <p>
	 * In the following rules, the computed 'text-indent' value of "h1" elements
	 * will be 36px, not 45px, if "h1" is a child of the "body" element.
	 * <p>
	 * body { font-size: 12px; text-indent: 3em; /* i.e., 36px}}
	 * <p>
	 * h1 { font-size: 15px }
	 * <p>
	 * 
	 * So when computing the value of text-indent, with this method, the value
	 * of font-size is retrieved from body, instead of h1.
	 * 
	 * @return the absolute dimension value.
	 */
	public DimensionValue getAbsoluteValue( )
	{
		
		
		Object value = getValue( );
		if ( value instanceof String )
		{