OccBin: provide more informative error messages if name tags are not identical
If the name
-tags are not identical as in
[name = 'borrowing', bind='borrcon']
lb = 0;
[name = 'borrowing1', relax='borrcon']
b = M*y;
the error message will be
ERROR: the number of equations marked [static] must be equal to the number of equations marked [dynamic]
We need to make sure that the tags come in pairs and that there is no other equation that already uses that name (as to have three equations with the tag).