Update packages, setup Jest for testing. Implement and test store/data/GROUP_NODES (#13) for general groups. Updated dataset format.

Needs testing. Optionfor grouping available after selection in NodeSelection

Added visuals for group in GraphNode

GraphNode: instead of move event now runs callback passed down from NetworkGraph.

Prepare for production: turn off history mode in routing, set public path, BaseIcon: use webpack imports for assets instead

Graph: show simulation variables, pause/restart controls; solve performance issues by adding temporary links when running force simulation – closes #21

Store/interaction: fix selecting a node with id=0

BaseIcon: fix image dragging.
GraphNode: rename event for consistency.
Minor formatting.

Move graph links to component. Add sticky paws and link markers for different link types. Implements #2

You may now experience performance issues when using devtools (maybe it's becuase vue-devtools only).

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.

Graph: add node dragging, popover. Make Toolbar.vue for interaction tools, make Workspace.vue for high-level operations - fetch store data and show graph/tools as component.

Proposed data copy for d3-force, GraphNode has new visuals.

Workspace.vue: use only d3-force to create test graph - no
interaction/store, nodes as components in Graph/GraphNode.vue

main.js: added vuejs-logger and automatic global registration of Base* components