Use List instead of IVec in DependencyHelper.getSolution()
Currently, the DependencyHelper class returns an IVec object, i.e. a Sat4j specific data structure.
Since the DependencyHelper is supposed to be embedded in Java software, it is probably wise to use only Java classical data structure to interact with that class. We could use for instance a java.util.List object instead of an IVec.
The main issue here is that it would break the API: the DependencyHelper class exists since Sat4j 2.1.