option changes to facilitate various testing.  the existing option <bool>auto-advance-first-turn is changed to <int>auto-advance-n-turns, and a new option <bool>auto-quit is added. They are both compatible with --quickstart and with --load

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7735 dbd5520b-6a0a-0410-a553-f54834df5b05