Prevent individual tabber tabs from line-breaking

Created by: mszabo-wikia

Currently, tabber navigation can only line-break if one of the tab contains spaces. Because of this, tabber navigation can grow really long (if there are no spaces in navigation content), or generate unwanted line-breaks in the middle of tab content.

This PR addresses the issue by adding manual breakpoints after each tab (<wbr>), and specifying individual tab contents to never wrap. Additionally, tests were added.