Include `seed` to argument parser

[tsirif]

Hello there!

I would like to make a PR which would include the following things:

• [x] Add an cmd line argument for a seed.
• [x] Create a setter functions which takes a seed as an argument and reseeds relevant PRGs with it.
• [x] In exp.save save a "current" seed along with other stuff.
• [x] Modify "reload" routines to reseed properly.

Do you agree with these modifications? Where would they be most appropriate to include?

Also, what is the current status regarding the resumability of a specific named experiment? Some optimizer objects are not stateless, are they also saved? and if they are not, should they?

Thank you!

[rdevon]

What is the high-level goal 2-4?

[tsirif]

To ensure that an experiment is reproducible with a specific seed, regardless if it was interrupted and resumed at some point or not.

[rdevon]

OK, let's see your PR then. Thanks for working on this!