Frontend notification update

This merge request both:

• Fixes the issue of notifications sometimes not showing
• Changes the notifications system to only show one notification. If a new notification is submitted while another is showing, the current notification will be overwritten if the level of the new notification is greater or equal than the current level

merged

By Ruben Keulemans on 2018-06-18T16:06:12 (imported from GitLab project)

mentioned in commit a1fbd045

By Ruben Keulemans on 2018-06-18T16:06:12 (imported from GitLab project)