parlitools 0.3.0

• parlitools no longer stores local council party data. The most up-to-date
  data on the political make-up of local councils and individual councillors
  can be be accessed with the new council_seats() function.

• Updated the leave_votes_west dataset to include the latest best-estimates
  of constituency level votes from Chris Hanretty and the actual votes, where
  known.

• Fixed errors caused by duplicated vignette names.

• Eliminated some dependencies.