Bucket of Commits

This contains ~~five~~ ~~SIX~~ *SEVEN* commits that each fix a (relatively) minor issues:

  * Submission table filtering (in assistant view) is working now
  * Small mistake in assets/js/aaltoplus.js
  * Prototype phase is now over
  * Added many favicons
  * Fixed easter egg :)
  * Metadata fetching when creating exercise works now again, same problem as in 840d707
  * Added GPL v3 license