Add optional quantum random number generator

[saranvdev]

There are some sites with api for getting quantum random numbers, I think it'd be nice to have:
https://qrng.anu.edu.au/API/api-demo.php

They're producing random numbers by reading void fluctuations or something like this.
Anyway, these are 100% random numbers.
Some online RPG sites are already using quantum numbers.

The only problem that I can think of, this feature will need internet connection.

[calebj]

We could do this by optionally depending on quantumrandom, I think.

Implementing a subclass of random.Random based on that package isn't within the scope of python-dice, but I can PR it to quantumrandom and add an option to supply a custom Random instance. That would also allow users to roll dice using random.SystemRandom if they want.

[calebj]

I've implemented a version of Random that uses quantumrandom with caching, but I'd like to add background thread fetching before posting it.

[calebj]

I've posted the interface here. I'll work on the dice lib modification next.

[calebj]

PR'd the quantumrandom change as lmacken/quantumrandom#22, and you can specify the random engine used by python-dice as of v2.4.0, which is live on PyPI now.