Add tools: NodeSelection, NodeDetail. Add store/interaction for maintaining...

Add tools: NodeSelection, NodeDetail. Add store/interaction for maintaining shared state for UI/tools. Style using SASS.

NetworkGraph: fixed initial :transform on g-elements; call store/interaction actions.

GraphNode: connect isSelected, isFocused with store/interaction.

Workspace: tools are rendered here, move NodePopover from graph.

_workspace.sass: Variables and mutual styles for importing into components.