MultithreadCorner/Hydra: Hydra 2.5.0

Hydra 2.5.0 Eigen is not being distributed with Hydra anymore. Eigen will remain an dependency for foreseeable future. New facility to update Thrust and CUB. New namespaces hydra::hydra_thrust and hydra::hydra_cub defined. New lazy implementation of hydra::Splot. New hydra::PhaseSpace interface, with constructors taking the mass of the mother particle as well. Ctors also protected against inconsistent arguments via exception throwing. New algorithm hydra::sobol support up to 3667 dimensions Re-implementation of the impacted examples. Many bug fixes across the tree..