Double middleware support

What's new

• applyMiddleware - Add middleware to suber.
• applyReduxMiddleware - Any Redux middleware which handles side effects and dispatches new actions when done are now compatible for usage with suber.
• Subscribers fn calls are now being called async.
• Catch all messages on all channels with take('*', cb)
• Add compatibility tests for createReduxMiddleware and popular middleware like redux-observable and redux-saga.

Breaking changes

• Remove emitFn. Replaced by applyMiddleware which is broader and covers this use case.