Changes

SILHS reproducibility (#1258)

* Making the SILHS random number generator on GPUs more reproducible by relying on the lh_seed input every call, which is the same as how the CPU randoms work. Also ensuring that the seed changes each timestep, just to prevent generating the same randoms on different timesteps. Since this does change the randoms, it is BIT_CHANGING for silhs enabled runs.

* Improving comment