Squashed commit of the following:

commit fe26d4b3f8417b9986980158f0b399ae1706de93
Author: Antje Petersen <antje.petersen@desy.de>
Date:   Tue Sep 17 14:34:03 2013 +0200

    Book: Added chapter about WriteToken.

    Target: master

commit 6d20af9e8f93588555c6abafbc9d2abdb1b3a2f0
Author: Antje Petersen <antje.petersen@desy.de>
Date:   Tue Sep 17 14:31:59 2013 +0200

    Book: Added config-write-token.xml to config.xml

    Target: master