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/src/org/eclipse/birt/report/engine/script/internal/element/Group.java
{
	
	public Group( GroupHandle handle )
	{
		super( handle );
	}
	public String getKeyExpr( )
	{
		return ( (GroupHandle) handle ).getKeyExpr( );
	}
	public void setKeyExpr( String expr ) throws ScriptException
	{
		try
		{
			( (GroupHandle) handle ).setKeyExpr( expr );
		}