New: Added support for double click events

[shashankshukla96]

This PR will add support for double click events, the library exposes the 3 new events

1. NODE_DOUBLE_CLICK :  Triggered when a node on the canvas is double clicked
2. EDGE_DOUBLE_CLICK : Triggered when an edge is double clicked.
3. MOUSE_DOUBLE_CLICK: Triggered when the canvas is double clicked.

For example, to handle NODE_DOUBLE_CLICK event we can use

orb.events.on(Orb.OrbEventType.NODE_DOUBLE_CLICK , (data) => {
      console.log("Node Double Clicked", data);
})

[tonilastre]

Btw, please run the npm run lint (and npm run lint:fix) to fix lint issues. I've added automatic lint in the baseline branch that will be used for your PR: #51

[tonilastre]

Great fix. There is one issue left around the consistency of events, so please check it out!

[tonilastre]

Looks great. Please run npm run lint:fix once more and commit, there are 2 standing issues. Btw, from the next version forward, linting will be in the pre-commit hook.