Notifications on Firefox

Ahoy,
I added in some code to allow for notifications to be shown on Firefox. We have been running the modified code for about a week now and I haven't noticed any previous functionality being broken, but that doesn't mean I wouldn't appreciate someone taking a closer look at my code :) 

In the changes I ended up removing the variable "supportsNotifications", if this variable needs to stay available please let me know and I will put it back in an resubmit the pull. Thanks for a great IRC viewer!