Check that the fasta sequence and residues in the benchmark pdb match

[linucks]

If the sequence given to ROSETTA to model and that in the native pdb file (supplied with the -native_pdb flag) don't match, then the benchmarking will crash with:

INFO: Using single structure provided for all model comparisons
INFO: Direct comparison of models and structures
----------------------------EICV-TA
TSSVLRSPMPGVVVAVSVKPGDAVAEGQEICVIEA
Traceback (most recent call last):
  File "/home/jmht/ccp4-7.0/lib/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/home/jmht/ccp4-7.0/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/home/jmht/ample.git/ample/util/tm_util.py", line 658, in <module>
    main()
  File "/home/jmht/ample.git/ample/util/tm_util.py", line 642, in main
    tmapp.compare_structures(args.models, args.structures, fastas=args.fastas, all_vs_all=args.allvall)
  File "/home/jmht/ample.git/ample/util/tm_util.py", line 437, in compare_structures
    pdb_combo = self._mod_structures(model_aln, structure_aln, model, structure)
  File "/home/jmht/ample.git/ample/util/tm_util.py", line 510, in _mod_structures
    raise RuntimeError(msg % (model_name, structure_name))
RuntimeError: Differing residues in model and structure. Affected PDBs S_00000012_10_0dqz6csdh8_mod - 2JKU_std_std

We should check that the sequence and residues in the PDB file match at the start