Show Nim: Mummy, a new HTTP + WebSocket server that returns to the ancient ways of threads

[guzba]

* Yes, for global memory you'll want to use atomics / locks. Async does not 
actually save you from this either, races are easy to create with await so I 
consider it a wash.
* I just kind of randomly set that. Honestly set it to 1000 threads if you 
want, it doesn't matter, better to be super high unless you're doing intense 
computation per request.