Virtual Node Support

[agubler]

Type: feature

The following has been addressed in the PR:

• There is a related issue
• All code has been formatted with prettier as per the readme code style guidelines
• Unit or Functional tests are included in the PR

Description:

Adds support for virtual nodes in the rendering engine. This enables nicely returning arrays when using TSX.

render() {
    return (
        <virtual><div/><div/></virtual>
    );
}

Resolves #424