Update instances of prop to use this

[n8rzz]

Update direct usages of prop inside classes. Instead of a class setting class properties to prop use this.

However, for now, we must maintain the references to the original prop values so we don't break everything.

the current workaround is:

const aircraft = {};

export default class Aircraft {
    constructor() {
        this.aircraft = aircraft;
        prop.aircraft = aircraft;
    }

This way we can maintain the original props, but still use class properties in the usual way.

---

There are also references to prop values from other classes sprinkled throughout, those are not being refactored [yet] with this issue.

[n8rzz]

work started on branch feature/ATC-43

[n8rzz]

gameController updated with #96

[erikquinn]

This issue was moved to openscope/openscope#62