Made changes to reference diagram

Merging Testing to Master Branch

Merge branch 'Testing/Practice' of https://github.com/cybersoton/Recommending-and-modelling-optimal-security-practices-for-smart-grid-connected-IoT-devices into Testing/Practice

A basic protocol modelling the sending of data and confirmation of receiving

Added a nonce and variable that can be used to send and recieve

very basic protocol