add a bunch of new icon sizes
Support new web app manifest
More icon improvements
Improved the icons (less cropping of edges of circle)
Some more changes to the manifest, but it doesn't seem to be working
Add some comments to explain what the manifest actually is
Have an alert for Computer Science Week
Add alert message for computer science week
Change version to tutorial
Fix typo
Remove unnecessary classes for alert
Merge branch 'tutorial' into development
Comment out alert code
Merge branch 'tutorial' into development
Merge branch 'development'

Conflicts:
	app.yaml