Reduce memory usage for ensemble problems

[ChrisRackauckas]

@henry2004y

ensemble_prob = EnsembleProblem(prob; prob_func)

ensemble_prob = EnsembleProblem(prob; prob_func, safetycopy = false)

@henry2004y

I guess if I use a vector type for the parameter, p = Any[10, 28, 8/3], then probably the parameters are referring to the same memory?

Use p = [10, 28, 8/3] instead.