UCB1, Thompson algorithms

[MilaKyr]

Hi, thanks a lot for the great crate! I'm planning to use it in my project :)

I wanted to add UCB1 and Thompson algorithms to the crate. Also wanted to add separate update for selected arm and for reward received, as I will be using it in multi-threaded environment where reward can be delayed up to a few minutes. I think it is a quite common use case and would be useful in the crate.

What do you think?

[Ragnaroek]

Great. I will happily accept Pull Requests in that direction!