Backend message management

[emgrasmeder]

The backend needs to receive, parse, and respond to messages. It also needs to package events and deliver them to the front end.

I think there should be a Message Manager in the backend which:

1. Takes a map type and returns a byte array, which could be used here
2. Parses the message received from the frontend (potentially as a map) and incorporates the update as appropriate

• Let's start with a "Clear All" button (Put a "clear-all" button at the bottom of the grid #23, Backend to have an account of what exists in the front end #20)
  • The front end needs to send updates to the backend
  • The back end needs to keep track of what has happened on the front end
  • The clear all button will update both the front end and the back end and set each cell to its default state