Working on #178 #143
Merge branch 'master' of https://github.com/TCA-Team/TumCampusApp

Conflicts:
	app/src/main/java/de/tum/in/tumcampus/activities/ChatActivity.java
	app/src/main/java/de/tum/in/tumcampus/adapters/ChatHistoryAdapter.java
	app/src/main/java/de/tum/in/tumcampus/services/GcmIntentService.java
	app/src/main/res/values/strings.xml
Working on #143