implement simpleMiddleware for koa

[eudaimos]

The current koa middleware implements an interface to be used for extending a TAO Signal Network across physical networks using HTTP. It is a full interface and would not be used to build a REST API from koa with tao.js underneath.

Implement a simpleMiddleware for koa that acts more like a koa middleware to allow embedding a TAO Signal Network into a koa app that does not require using the TAO HTTP Interface used for extending a TAO Signal Network over HTTP.