Saltnado: tornado implementation of salt-api

Salt-api gives a restful interface to Salt. Salt in itself is effectively just a pub/sub async messaging bus. The current implementations of salt-api use blocking IO to communicate to salt-- which is async. This implementation uses salt's event system to create a single process using the event system to create non-blocking communication with salt. This allows for a single process to handle a large amount of concurrent requests quickly and cheaply. 

This implementaion is only missing the WHEEL client-- primarily because it has no async interface. I plan on adding it, but figured i should get this merge request going sooner rather than later.

I have run local tests against this-- but have been unable to get the tests in the repo to run (on either this one or the old implementations).