Add Support for Botkit 4

[Naktibalda]

I updated javascript code to work with Botkit 4. It uses a different storage system now. Because Botkit uses promises everywhere now, I used Promises in utils.js too, but the interface of middleware remains unchanged.

BREAKING CHANGES:

• This change is incompatible with Botkit 0.7.*, so a major version bump is required.

[germanattanasio]

@Naktibalda can you fix some of the open issues along with this PR?

[Naktibalda]

I converted code to Typescript.

Usage in Typescript:

import {WatsonMiddleware} from 'botkit-middleware-watson';
const watsonMiddleware = new WatsonMiddleware(config);

Usage in Javascript:

const WatsonMiddleware = require('../lib/middleware/index').WatsonMiddleware;
const middleware = new WatsonMiddleware(config);

[Naktibalda]

Because this middleware is a class now, it must be registered this way: controller.middleware.receive.use(watsonMiddleware.receive.bind(watsonMiddleware)); (I wasted hours trying to figure out why controller.middleware.receive.use(watsonMiddleware.receive); wasn't working.)

[Naktibalda]

Botkit 4.0.1 was released yesterday, so Botkit 4 is complete.

@germanattanasio Please review, merge and release 2.0.0. Another option is to make it 4.0.0 to catchup with ibm-watson 4 and Botkit 4.

I updated README, but samples are still outdated.

[germanattanasio]

@Naktibalda In order to merge this and trigger a major release we need to update or remove the multi-bot sample. I vote for removing that sample and point users to botkit.

[Naktibalda]

I agree on removal of multi-bot. I think that even the README of simple-bot should crearly state that "This is just a sample, please follow documentation of Botkit to create a new bot and then plug Watson middleware into it".

[codecov-io]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@3fc1bdc). Click here to learn what that means. The diff coverage is 78.5%.

@@           Coverage Diff            @@
##             master    #174   +/-   ##
========================================
  Coverage          ?   78.5%           
========================================
  Files             ?       2           
  Lines             ?     107           
  Branches          ?      22           
========================================
  Hits              ?      84           
  Misses            ?      19           
  Partials          ?       4

Impacted Files	Coverage Δ
lib/utils.js	100% <100%> (ø)
lib/index.js	65.15% <65.15%> (ø)

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[Naktibalda]

Thanks