Improve the extension description on addons.mozilla.org

[Korb]

At the moment, judging by the extension description and its screenshots on addons.mozilla.org, it can be assumed that it can only display pop-up notifications. I propose to fix this, at a minimum, by adding the following screenshot, and adding a list of its capabilities to the description of the extension, in addition to displaying a pop-up notification.

[ion201]

Thank you for the suggestions, I will look into this when I have a chance soon. The README on this repo could use some work too.

I agree that the the AMO description is probably long overdue for some additional explanations and clarification. I can see how the options page is not easily discovered for users that aren't already familiar with it.