Update Russian translation
Update po files
Display serverlist flags as icons
Remove vertlabels from main menu and relayout a bit
Fix segfault when dragging mouse out of mainmenu window (#1910)
LuaPerlinNoiseMap: Fix 3d noise safety check
Update german translation
Provide more info if a subgame is not valid/found
Fix misleading error when exiting the client from the main menu
Revert "Update Russian translation"

This reverts commit e4e4324a30d6bcac5cc06c74e955e4941b14bd38.

Conflicts:
	po/minetest.pot
	po/*/minetest.po