Version 3.6.18

Stable release for Little Navmap update.

• Reworked weather URL test functions to allow API keys. Added METAR format reader for IVAO JSON.
  Added header parameters to HttpDownloader for API keys. #864
• Now skipping empty lines in X-Plane file header which appear in some malformed apt.dat files.
• Fixed issue in scenery library loader where airports were wrongly recognized as MSFS POI dummies.
• Corrected closed airport logic for MSFS. Now fully relying on closed airport flag for MSFS to have
  consistent behavior with the simulator. This can result in closed airports having open runways and
  open airports having all runways closed. #876
• Fixed issue where all airports were recognized as add-on with MSFS update 9.
• Corrected detection of MSFS Navigraph update due to name change in manifest.json. This fixes
  issues where add-on airports did not update scenery correctly.
• Fixed issues for updating airports by disabling a corner case from FSX and P3D which does not
  apply to MSFS. Before a feature was not updated if the new airport did not contain new
  features like aprons or taxiways. Example LICC add-on.
• Fix for Windows icon notification preventing toolbar hiding on windows with Raise Windows options enabled.
• Fixed issue when downloading NAT tracks containing PBCS TRACKS AS FOLLOWS/V W X/END OF PBCS OTS.
• Now dropping all artificial waypoints created only for procedure or airway resolution.
• Fixed issues with anti-meridian detection when point is on meridian and date line crossing was not
  always detected. This resulted in kinks in flight plan or measurement lines.