Fix mod priority. Add user mod support. Fixes #1838.

This was SVN commit r13167.

binaries/system/readme.txt

@@ -22,10 +22,11 @@ Random maps only:
 -autostart-players=NUMBER		NUMBER of players on random map
 
 Configuration:
--conf:KEY=VALUE		set a config value (overrides the contents of system.cfg)
+-conf=KEY:VALUE		set a config value
 -g=F				set the gamma correction to 'F' (default 1.0)
 -nosound			disable audio
 -onlyPublicFiles	force game to use only the public (default) mod
+-noUserMod			disable loading of the user mod
 -shadows			enable shadows
 -vsync				enable VSync, i.e. lock FPS to monitor refresh rate
 -xres=N				set screen X resolution to 'N'