Bug 153853 [Regression]The bound column names must be unique within the entire table.
Regression case Regression_136421(under org.eclipse.birt.report.tests.model) failed. Expected result: Model will avoid adding a duplicate bound column name within a table.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
assert root != null;
			handleList.add( element.getHandle( root ) );
		}
		return handleList;
	}
	/**
	 * Returns the libraries this report design includes directly or indirectly.
	 * Each in the returned list is the instance of <code>LibraryHandle</code>.
	 * 
	 * @return the libraries this report design includes directly or indirectly.
	 */
	public List getAllLibraries( )
	{
		return getLibraries( IModuleNameScope.ARBITARY_LEVEL );
	}
	/**
	 * Returns included libaries this report design includes directly or
	 * indirectly within the given depth.
	 * 
	 * @param level
	 *            the given depth
	 * @return list of libraries.
	 */
	protected List getLibraries( int level )
	{
		List libraries = module.getLibraries( level );
		List retLibs = new ArrayList( );
		Iterator iter = libraries.iterator( );
		while ( iter.hasNext( ) )
		{