MC56: Read a file or a supplementary file held in Rutherford-Boeing format

To read a file held in Rutherford-Boeing format. This may contain either a sparse matrix or supplementary data. There are many types of supplementary data for which the user should read the documentation on the Rutherford-Boeing Sparse Matrix Collection (RAL Report RAL-TR-97-031). These include right-hand sides, solution vectors, orderings, eigenvalues etc.