ActionBarTabs in InvitationBase class
ActionBarTabs, InvitationBase class plus subshells
Merge branch 'master' of https://github.com/ese-unibe-ch/ese2013-team6
More GUI shell, need to commit for pulling
Merge branch 'master' of https://github.com/ese-unibe-ch/ese2013-team6

Conflicts:
	src/MensaUniBe/res/values/strings.xml