Evaluate twisted event loop

[dnephin]

Is it possible we could replace the twisted event loop with monocle or another alternative?

It would most likely mean replacing the ssh client with paramiko or something related.

[dnephin]

If we do continue to use twisted, the reactor imports should be cleaned up so that a reactor instance is passed around instead of using a global import.

[irskep]

I'm definitely in support of kicking Twisted out and using Paramiko for SSH. We don't have that many Twisted API calls throughout the code, just a few key places. And lots of test cases, which is the hard part I guess.

I'm not familiar with monocle.

[dnephin]

As a first pass all references to twisted internals will be moved into a single eventloop module, and the rest of the code will make calls to that module. This should make it much easier to swap out twisted later on, if necessary.