BlockGSStep: Default value for BitVector
The third of four template arguments of the new BlockGSStep class is 'BitVector'. In the vast majority of the cases, this will be
Solvers::DefaultBitVector_t<Vector>
Please provide this as a default template parameter.
This may involve switching the order of the template parameters around[1], which is fine with me, even though it will break things.
[1] Unless one provides a default value for the LocalSolver template parameter, too, which I wouldn't mind.