Incorrect bundle splitting if single bits are split from a larger vector

[Flojo101]

Detailed description in FEntwumS/FEntwumS.NetlistViewer#35

Potential fixes are as follows:

1. Keep the basic design as is. This would keep bundle splitting at the cell output ports. The result for the OneWare template could be like Q[19:0], Q[20], Q[23:21]. While using just two ports is possible (Q[23:21; 19:0], Q[20]), such an output would quickly get illegible whenever more than one split occurs.
2. A more involved option would be two split the subsets from the connecting edges directly. This would entail placing dummy nodes at ech split, with dedicated ports for vector in, vector out and split out. Such a node and its ports would be of size zero to avoid visual clutter. A dummy node is necessary to prevent unclear labeling of the different vector splits, since just adding additional outgoing edges to cell outports does not guarantee label placement and where the split occurs. Additionally, such a split would be difficult to distiguish from a split where a given signal is routed to several cells without being split. Such a distinction is not easy for both the backend and the frontend.