0.15.1

Sway 0.15.1 is a bugfix release containing 58 changes from 18 contributors.

• Update to json-c 0.13 (@besser82)
• Documentation corrections (@Zer0-One, @madblobfish)
• Portability fixes (@johalun)
• Output scale now preserved upon reloads/hotplugs (@sideshowdave7)
• Closing fullscreen windows in nested containers no longer crashes (@SirCmpwn)
• swaygrab more gracefully handles errors (@ggreer)
• Fixes to some minor tray issues (@etam)
• Fix security grants for swaylock -f (@4e554c4c)
• Clear password buffer after checking it in swaylock (@ggreer)