Log Message:
Update to 20180827. Changes since 20180405:
- fix and cleanup wind barb rendering along route
- ADD max wind in ReportDialog
- ADD comfort status in the WeatherRouting panel and ReportDialog
  This allows to:
  * Display directly in the table what will be the worst
    sailing comfort conditions found on the way.
  * Display in the ReportDialog the most comfortable route and date
    to start.
- ADD option for a safety distance from land
  The idea is to add a safety distance to calculate the weather route from
  any land that can be found on the way.
- various cleanups and bug fixes