LinearCombination.java evaluate method

Hi all,

I think there is a problem with the evaluate() method in `relations.objects.LinearCombination`.
This line seems fishy if the condition is true:
```
final FieldT value = index == 0 ? one : input.get((int) index).mul(terms.get(i).value());
```
If `index == 0`, we want to add the constant value of the linear combination, which should be 
`terms.get(i).value()`, not `one`.