Missing Installation Guide

[wongjasont]

Would be very helpful If you could add an installation guide in the README.

(I'm not a python user but I don't have a choice because reality is there are only very few out here) I really like the modbus simulator in GUI (https://github.com/riptideio/modbus-simulator) - and that project refers to this one for the CLI version of the simulator which I very much need.

[dhoomakethu]

@wongjasont just run pip install -r requirements to get started with the simulator. I will add the instructions to README soon