MultithreadCorner/Hydra: Hydra 2.5.0

Hydra 2.5.0

1. Eigen is not being distributed with Hydra anymore. Eigen will remain an dependency for foreseeable future.
2. New facility to update Thrust and CUB. New namespaces hydra::hydra_thrust and hydra::hydra_cub defined.
3. New lazy implementation of hydra::Splot.
4. New hydra::PhaseSpace interface, with constructors taking the mass of the mother particle as well. Ctors also protected against inconsistent arguments via exception throwing.
5. New algorithm hydra::sobol support up to 3667 dimensions
6. Re-implementation of the impacted examples.
7. Many bug fixes across the tree...