…go#4)

* Add decorator to mark middleware as async; fix middleware tests

* Simplify async middleware decorator

* Don't log about adapting middleware if DEBUG is false

…he unnecessary open threads

…ethods on ipython

… can be generalized

They actually do as of this commit, and the middleware appears to work
fine, but I'm sure there's some threading issues to be caught if nothing
else.

…go#4)

* Add decorator to mark middleware as async; fix middleware tests

* Simplify async middleware decorator

* Don't log about adapting middleware if DEBUG is false