Merge pull request #1276 from rafwiewiora/multi_model_conect

Add CONECT bonds for multi-model pdb files 

wrappers/python/simtk/openmm/app/pdbfile.py

@@ -154,7 +154,7 @@ class PDBFile(object):
         # Add bonds based on CONECT records.
 
         connectBonds = []
-        for connect in pdb.models[0].connects:
+        for connect in pdb.models[-1].connects:
             i = connect[0]
             for j in connect[1:]:
                 if i in atomByNumber and j in atomByNumber: