group menus by day

add option to show menus grouped by day
fix npe

fix npe while loading lvas
Merge pull request #27 from marunjar/dev

pull Dev branch into master
fix npe

fix npe while loading exams
group menus by day

fix creation of tabs
push version

push version to 0.20
change exception handling
push version

push version to 0.21
Merge remote-tracking branch 'origin/master' into new_ui

Conflicts:
	aNewJKUApp/src/main/AndroidManifest.xml
	aNewJKUApp/src/main/java/org/voidsink/anewjkuapp/MenuCardArrayAdapter.java
	aNewJKUApp/src/main/java/org/voidsink/anewjkuapp/activity/MainActivity.java
	aNewJKUApp/src/main/java/org/voidsink/anewjkuapp/fragment/MensaFragment.java