od 0.4.0

• od_disaggregate() can now take route networks as inputs
• od_disaggregate() is now used as a 'back-end' for od_jitter() where possible by default
• New pd argument in points_to_od() allows calculation of OD pairs associated
  with destinations that have a different geometry than the origins (#41)
• Remove 'old style CRSs', preventing warnings emitted by the sf package