Version 6.0.2 is ready

This release brings only fixed bugs for stable release. Binaries are available for Linux and Windows (both 64-bit). For more info how to use AppImage on Linux, please see: https://docs.appimage.org/user-guide/run-appimages.html. Below are changes since the last stable release:

Changed

• Updated README.md

Fixed

• Showing crafting recipe as uncraftable when materials are present
• Hiding close button after setting base, event, accepted or available mission,
  story as the player's ship's destination or showing it on map
• Hiding guns orders in combat when nobody is assigned to them
• Crash on setting new crew member to empty position in combat
• Crash on setting new crew member to empty gun in combat
• Setting gunner in combat