Linking between text editor and visualization

[sehilyi]

It would be really helpful for editor users if we visually link between the editor and the rendered visualization. For example, to help find a corresponding track definition in the text editor from the rendered gosling visualization, we can highlight (or jump to) the track spec by hovering (or selecting a cotext menu) from a gosling visualization. Similar thing can be supported for different way (text editor -> highlight corresponding track).