COVID-19 wót chopinlytlyt

This version adds the "job news" tab which specifically provides job-related information around the market.

(**The purpose of developing this add-on is providing the aggregated information about the covid-19 pandemic happening around the world. It is originated from the website that is maintained by our team for the same reason. Our data update is more timely than most of the current covid-19 stat apps, which aims to provide the most current information about the event. Now, instead of typing the url in browser, we develop an add-on which will be more convenient for users to access to the information from our website.**)

This add-on will be an extension of Firefox explorer. After installation, a small icon will be added on the browser. The add-on will not open any page in browser. When clicking on the icon, a small window will appear under the icon, showing all the information.