Remove eventmachine

Calling `EM.defer` in effect just calls `Thread.new` with a wad of overhead. The only risk here is that a LOT of threads get created, but I think this is the same problem you were getting when you could only read ~300 messages. I don't think this library currently needs EventMachine at all.

I've spent a couple of hours reading about how threads work in Ruby. I've posted some thoughts on Flowdock and I highly recommend this article series: http://www.jstorimer.com/blogs/workingwithcode/8085491-nobody-understands-the-gil

@mmmmmrob, @malcyL - thoughts?