Rewrote emulator/core package & moved to app/main.

[tonyanziano]

#1969

===

Highlights:

• Removed emulator/core & emulator/cli
  • emulator/core has been moved under app/main/server
  • emulator/cli has been removed since it was not being used anywhere, the current structure of app/main/server is organized in a way that it should be invokable via a CLI if we want to bring that functionality back
• New folder structure for REST server backend of the Emulator should be easier to understand at a glance:

main/
  src/
    server/            // where what was previously emulator/core lives
      routes/          // this is where all the endpoints and their handlers live
        channel/       // what the bot interacts with
        directLine/    // what the client interacts with (user through Web Chat)
        emulator/      // used for firing actions within the app (can call from client to check for updates or write to disk, etc.)
      state/           // classes for REST server in-memory state (conversations, endpoints, users) -- what used to be known as facilities

• Pruned a lot of unnecessary code having to do with handling routes
• Consolidated components under the Emulator.ts class so that instead of accessing conversation state via emulator.framework.server.botEmulator.facilities.conversations, it can now be accessed via emulator.server.state.conversations
• Deprecated all /v3/botstate/ endpoints (See blog post for more info)

[coveralls]

Coverage increased (+0.9%) to 68.461% when pulling 9094f7e on toanzian/core-rebased into 1f0e1e6 on master.