Leylines, now also for Linux!

Leylines is now available for Linux. This has been tested on Ubuntu 22, and it will most likely run on any recent or semi-recent distro that supports the Allegro library. Aside from that, this patch includes bugfixes as follows,

• Fix closing certain popups by clicking beside them.
• Fix custom portrait thumbnails.
• Fix keyboard shortcuts in wizard creation and editor.
• Fix switching to windowed mode at runtime.
• Fix worker count when starting a new scenario.
• Increase morale effect of ghosts.