Vakya Analysis - Need multi-edges in graphs

[kmadathil]

Currently, we're limited because we can't have multiple possible edges between nodes (our underlying datastructure is a digraph)

• gaunakarma - (karta aNau) for Rijanta dhAtu
• gaunakarma for dvikarmakas
• BAvalakzaRa vs aDikaraRa
• non-kAraka vibhaktis
  (Possible more)

To fix this, we need to change the underlying datastructure into a Multigraph.

[kmadathil]

Fixed.