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
/**
	 * Returns the library handle with the given file name. The filename can
	 * include directory information, either relative or absolute directory. And
	 * the file should be on the local disk.
	 * 
	 * @param fileName
	 *            the library file name. The filename can include directory
	 *            information, either relative or absolute directory. And the
	 *            file should be on the local disk.
	 * @return the library handle with the given file name
	 */
	public LibraryHandle findLibrary( String fileName )
	{
		URL url = module.findResource( fileName, IResourceLocator.LIBRARY );
		if ( url == null )
			return null;
		Module library = module.getLibraryByLocation( url.toString( ) );
		if ( library == null )
			return null;
		return (LibraryHandle) library.getHandle( library );
	}
	/**
	 * Shifts the library to new position. This method might affect the style
	 * reference, because the library order is changed.
	 * 
	 * @param library
	 *            the library to shift
	 * @param toPosn
	 *            the new position
	 * @throws SemanticException