Surfers Paradise

Major changes

• Add new function get_coastal_forecast(), which fetches the BOM coastal
  waters forecast

Minor changes

• Add spaces between sentences in some error messages when interacting with the
  BOM servers

• Enhance testing for get_historical()

• Handle checking multiple imagery files gracefully without returning warning
  message if more than one file is to be loaded in current session

• Update citations for package to reflect current package and paper citation