Methods
edgeText()
    Displays in the middle of the edge (typically cost/resource vectors or capacity/flow)
- Source:
nodeLabel()
    Displays inside of a node (typically its id)
- Source:
nodeText()
    Displays on top of a node (typically constraints or state variables)
- Source:
nodeX()
    X Position of a node
- Source:
nodeY()
    Y Position of a node
- Source:
onEdgesEntered()
    Called when new edges are entering
- Source:
onEdgesUpdated()
    Called when exisitng edges are updated
- Source:
onNodesEntered()
    Called when new nodes are entering
- Source:
onNodesUpdated()
    Called when exisitng nodes are updated
- Source:
update()
    The main function which triggers updates to node and edge selections.
- Source:
updateEdges()
    D3's Data Join of edge data with their visualization (lines)
- Source:
updateNodes()
    D3's Data Join of node data with their visualization (circles)
- Source: