Introducing an async library inspired by Go in Nim

[Alogani]

The next best thing in my opinion would be to add a NimGo-aware Channels. You 
would use NimGo in your main thread doing some I/O stuff and when there is a 
complex calculations, you transfer communicate with an OS thread. Or if you 
know you have to handle a lot of I/O, you can use multiple threads which each 
there own NimGo's dispatcher. But I don't know if I would add this feature 
soon, the existing implementation (after minor corrections) already fits my 
needs far beyond my initial expectations.