Extend Component class -> QASMComponent

[TrevorBurgoyne]

          Since we set `window.COMPONENT = this` on all components it may not be a bad idea to do the following

    class QASMComponent extends Component {
        constructor(props) {
            super(props);
            // Expose component in window
            window.COMPONENT = this;
        }
    }

And then have all of our components extend QASMComponent instead of Component. This would also be a place to put future custom Component-wide functionality.

Originally posted by @csolbs24 in #19 (comment)