Fix foreground flakes (layer 2+6) disappearing when moving camera in world wrap world

Fix hard-to-read text on campaign and training page in frontend at October 31 The text was yellow against a white background (the moon in the Halloween background). This is fixed by darkening the critical area.

Update outdated and broken holiday stylesheets Each style was updated by copying qt.css and then adjusting the required definitions such as background image and color.

Fix resurrection animation appearing at wrong position for some missions and styles

Report spawning visual gear in onGearResurrect

Add setting to disable audio dampening if losing window focus

Move max. number of crate spawns into variable

Fix visible seam between Sky.png and SkyL.png of Olympics theme

Lobby/room: Prevent opening context menu if no player selected (fixes bug #661)

Fix drill rocket exploding when digging at bounce/wrap world edge