Bug 168172 Add the get() and set() functions of HideDetail parameter on IGroup
Add the get() and set() functions of HideDetail parameter on IGroup, and thus enable the hidedetail shifting on the Group through eventhandler.
engine/org.eclipse.birt.report.engine.tests/test/org/eclipse/birt/report/engine/api/script/element/ElementTest.java
SharedStyleHandle style = factory.newStyle( "Style" );
		style.getPropertyHandle( "highlightRules" ).addItem( rule );
		designHandle.getStyles( ).add( style );
		tableHandle.setStyle( style );
		RowHandle rowHandle = (RowHandle) tableHandle.getHeader( ).get( 0 );
		IRow item = new Row( rowHandle );
		IHighlightRule iRule = new HighlightRuleImpl( rule );
		item.addHighlightRule( iRule );
		IHighlightRule[] rules = item.getHighlightRules( );
		assertEquals( 1, rules.length );
		iRule = rules[0];
		iRule.setColor( "red" ); 
		assertEquals( "red", iRule.getColor( ) ); 
		iRule.setDateTimeFormat( "mm dd, yyyy" );
		assertEquals( "mm dd, yyyy", iRule.getDateTimeFormat( ) ); 
		iRule.setFontStyle( "oblique" );
		assertEquals( "oblique", iRule.getFontStyle( ) ); 
		iRule.setFontWeight( "900" );
		assertEquals( "900", iRule.getFontWeight( ) ); 
		iRule.setStringFormat( "no format" );
		assertEquals( "no format", iRule.getStringFormat( ) ); 
		iRule.setTestExpression( "expression" );
		assertEquals( "expression", iRule.getTestExpression( ) ); 
		iRule.setColor( "#FFFFFF" );
		assertEquals( "#FFFFFF", iRule.getColor( ) );
		iRule.setOperator( "between" );
		assertEquals( "between", iRule.getOperator( ) );
		iRule.setValue1( "100" );
		assertEquals( "100", iRule.getValue1( ) );
		iRule.setValue2( "300" );