Routing algorithm doesn't account for overlapping lines

[harmen-xb]

When we would draw the same relationship twice, but for different roles of the relationship, the diagram file will contain two edges representing the relationships:

    edges:
      - id: ParentDataContainerToDataContainerRelationshipEdge
        relationship: ParentDataContainerToDataContainerRelationship
        sourceNode: DataContainerNode
        targetNode: DataContainerRelationshipNode
      - id: ChildDataContainerToDataContainerRelationshipEdge
        relationship: ChildDataContainerToDataContainerRelationship
        sourceNode: DataContainerNode
        targetNode: DataContainerRelationshipNode

But visually the lines are not separated, because they are drawn between the two same nodes:

The routing algorithm should be adjusted for this.

[harmen-xb]

Retested in v0.2.5 since the layout algorithm has changed. It is a bit improved, but the lines still overlap te much in my opinion.

There are two relationships between DataContainerRelationship and DataContainer in this diagram. Some examples how it looks like given the current libavoid algorithm:

Example 1:

Example 2: