Add option for starting in reverse order

[supertuxkart-sourceforge-migration]

Author: hikerstk

Add an option button for starting in reverse order of overall standings in grand prix. This way the players/AIs who are best would have an additional challenge to work their way through the field and their advantage of the jump start (often creating serial winners) would be reduced.

Migrated-From: https://sourceforge.net/apps/trac/supertuxkart/ticket/28

[supertuxkart-sourceforge-migration]

Author: hikerstk There is already an option in stk_config.xml, not sure that we need/want to expose this using a GUI.

[supertuxkart-sourceforge-migration]

Author: wardje Having recently looked into this, I assume I can't be the only one who wouldn't mind trying it out without breaking their head over how to do it (I was already thinking I was going to have to hack the source a bit). In case of adding, I'd say throw it in the options screen, not as something that appears during selecting.

[supertuxkart-sourceforge-migration]

Author: wardje Forgot to mention it here, but r11017 moves the setting to the user's configuration.