Changed the part where initially you see the symbol U in the addon icon if you haven't used the addon yet in the current browser session.
That was kind of pointless as later on, after having used the addon at least once, it will just display nothing anyways if you aren't actively using it to delete tabs.
So now there is no text if the addon isn't actively used.


Aside from that, some programming stuff was internally fixed up to make the code look more pretty and more understandable. even though the user wont usually get to see the code anyways.

Also changed version number form 0.9 to 1.0 since basically the program was already usable and finished and to my knowledge without bugs or errors before, so it only makes sense to give it the 1.0 to declare it a finished and working product.

If there are any feature requests, let me know and I might try to implement them if my programming skills allow it :-)