get_pointing_chain() now handles coreference chains w/ multiple antecedents - cf. Issue #40 - chains with multiple antecedents increase the number of chains, e.g.   a chain A -> B -> C&D will be turned into two chains:   A -> B -> C and A -> B -> D
get_pointing_chain() now handles coreference chains w/ multiple antecedents
- cf. Issue #40
- chains with multiple antecedents increase the number of chains, e.g.
  a chain A -> B -> C&D will be turned into two chains:
  A -> B -> C and A -> B -> D

arne-cl/discoursegraphs